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1
England, Phillip R., David A. Briscoe y Richard Frankham. "Microsatellite polymorphisms in a wild population of Drosophila melanogaster". Genetical Research 67, n.º 3 (junio de 1996): 285–90. http://dx.doi.org/10.1017/s0016672300033760.
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SummaryHighly variable DNA polymorphisms called microsatellites are rapidly becoming the marker of choice in population genetic studies. Until now, microsatellites have not been utilized for Drosophila studies. We have identified eight polymorphic microsatellite loci in Drosophila melanogaster and used them to characterize the genetic variation in a wild population from the Tyrrell's winery in Australia. Microsatellites were isolated from a partial genomic DNA library. All microsatellites consist of (AC)n repeats ranging from n = 2 to n = 24. Six loci were assigned to chromosomal location by genetic mapping, with three loci on chromosome II, one locus on chromosome III and two loci on the X chromosome. Up to four microsatellite loci were multiplexed in the same reaction. Microsatellite variation is substantially greater than allozyme variation in the Tyrrell's Drosophila population. 80% of the microsatellite loci examined are polymorphic, compared with 28% of allozymes. The mean number of alleles per polymorphic locus is 5·2 in microsatellites compared with 30 in allozymes. The average observed heterozygosity of polymorphic microsatellites is 47% compared with 26% for allozymes. Microsatellite variation in Drosophila melanogaster is similar to that reported for other insects. Higher variability commends microsatellites over allozymes for genetic studies in Drosophila melanogaster.
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Yu, Kangfu, Soon J. Park y Vaino Poysa. "Abundance and variation of microsatellite DNA sequences in beans (Phaseolus andVigna)". Genome 42, n.º 1 (1 de febrero de 1999): 27–34. http://dx.doi.org/10.1139/g98-100.
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Microsatellites or simple sequence repeats (SSRs) have been demonstrated to be abundant and hypervariable in some eukaryotic genomes. Although the presence of microsatellites is very well documented in many plant species, no information on microsatellites in beans (Phaseolus andVigna) is available. To assess the abundance and usefulness of bean microsatellites as genetic markers, 326 DNA sequences from the GenBank databases were searched. Sixty-one simple repetitive DNA sequences with 23 different types of repetitive DNA motifs were identified as potential microsatellites. Among these were 49 microsatellites from common bean (Phaseolus vulgaris) entries and 12 microsatellites from the genus Vigna. The most abundant type of microsatellite found in this search was that with di-nucleotide repeats of AT/TA. Microsatellites with tri- and tetra-nucleotide motifs were also identified. PCR analysis of 12 of the microsatellite-containing loci revealed that 11 of the 12 primer pairs could produce easily-scorable fragments, or groups of fragments. Allelic variation of the 11 loci was surveyed in 12 common bean inbred lines representing a diversity of germplasms. Seven of the 11 microsatellite loci were polymorphic and yielded 2-10 alleles. Analyses of the polymorphic loci in a common bean F6 recombinant inbred population showed that each segregated in a Mendelian fashion.Key words: microsatellite, simple sequence repeat, molecular marker, bean.
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Hale, M. L., A. M. Borland y K. Wolff. "High degree of conservation of nuclear microsatellite loci in the genus Clusia". Genome 48, n.º 5 (1 de octubre de 2005): 946–50. http://dx.doi.org/10.1139/g05-048.
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In plants, microsatellites and their flanking DNA are rarely conserved across a whole genus, let alone other genera in the same family. Therefore, the possibility of using microsatellite primers developed for a species across a large number of plant species in the same genus is often limited. Remarkably, dinucleotide nuclear microsatellites developed for Clusia minor and for Clusia nemorosa amplified homologous microsatellites in species across the whole genus Clusia. In this present study, we report on the DNA sequence variation across the genus of 3 microsatellite loci with varying levels of variation. Compared over the species, there was a correlation between the lengths of the microsatellite loci. Interrupts occurred multiple times and did not seem to lead to the death of the microsatellite. These highly conserved markers will be useful for studying the variable reproductive systems in the genus Clusia.Key words: microsatellite, Clusia, cross-species amplification, microsatellite evolution.
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Colson, Isabelle y David B. Goldstein. "Evidence for Complex Mutations at Microsatellite Loci in Drosophila". Genetics 152, n.º 2 (1 de junio de 1999): 617–27. http://dx.doi.org/10.1093/genetics/152.2.617.
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Abstract Fifteen lines each of Drosophila melanogaster, D. simulans, and D. sechellia were scored for 19 microsatellite loci. One to four alleles of each locus in each species were sequenced, and microsatellite variability was compared with sequence structure. Only 7 loci had their size variation among species consistent with the occurrence of strictly stepwise mutations in the repeat array, the others showing extensive variability in the flanking region compared to that within the microsatellite itself. Polymorphisms apparently resulting from complex nonstepwise mutations involving the microsatellite were also observed, both within and between species. Maximum number of perfect repeats and variance of repeat count were found to be strongly correlated in microsatellites showing an apparently stepwise mutation pattern. These data indicate that many microsatellite mutation events are more complex than represented even by generalized stepwise mutation models. Care should therefore be taken in inferring population or phylogenetic relationships from microsatellite size data alone. The analysis also indicates, however, that evaluation of sequence structure may allow selection of microsatellites that more closely match the assumptions of stepwise models.
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Röder, Marion S., Victor Korzun, Bikram S. Gill y Martin W. Ganal. "The physical mapping of microsatellite markers in wheat". Genome 41, n.º 2 (1 de abril de 1998): 278–83. http://dx.doi.org/10.1139/g98-009.
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Microsatellite markers represent a new class of genetic markers in plants. Such markers reveal a high level of polymorphism even in species with a narrow genetic base, such as hexaploid wheat (Triticum aestivum L.). We used a large set of such markers and 25 deletion stocks of 'Chinese Spring' in a deletion-mapping experiment to study the physical distribution of dinucleotide microsatellite markers in homoeologous group 2 chromosomes of hexaploid wheat. Thirty-one microsatellite markers identified 14 loci in chromosome 2A, 9 loci in chromosome 2B, and 10 loci in chromosome 2D. The microsatellite loci were evenly distributed along the chromosome length, marking 18 of 27 defined physical intervals, including centromeric, interstitial, and telomeric regions. The apparent random distribution indicates that microsatellite markers provide excellent coverage of the wheat genome.Key words: deletion stocks, group 2 homoeologues, microsatellites, wheat.
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Kushny, James E. E., John W. Coffin y Curtis Strobeck. "Genetic survey of caribou populations using microsatellite DNA". Rangifer 16, n.º 4 (1 de enero de 1996): 351. http://dx.doi.org/10.7557/2.16.4.1277.
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Microsatellite loci are highly variable regions of eukaryotic DNA that consist of tandemly repeated sequences of one to six nucleotides in length. The use of microsatellites and the Polymerase Chain Reaction (PCR) are powerful tools for quantifying genetic variation within and among individual populations. Recently, we have developed primers for caribou that amplify 4 microsatellite loci. These microsatellite loci were used to survey the genetic variation in populations of Barren-ground caribou (Rangifer tarandus groenlandicus), Peary caribou (R.t. pearyi) and Woodland caribou (R.t. caribou) of Canada. The four loci examined were all polymorphic, revealing high levels of heterozygosity (> 0.74) in all of the study populations.
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Long, Dustin R., Adam Waalkes, Varun P. Panicker, Ronald J. Hause y Stephen J. Salipante. "Identifying Optimal Loci for the Molecular Diagnosis of Microsatellite Instability". Clinical Chemistry 66, n.º 10 (24 de septiembre de 2020): 1310–18. http://dx.doi.org/10.1093/clinchem/hvaa177.
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Abstract Background Microsatellite instability (MSI) predicts oncological response to checkpoint blockade immunotherapies. Although microsatellite mutation is pathognomonic for the condition, loci have unequal diagnostic value for predicting MSI within and across cancer types. Methods To better inform molecular diagnosis of MSI, we examined 9438 tumor-normal exome pairs and 901 whole genome sequence pairs from 32 different cancer types and cataloged genome-wide microsatellite instability events. Using a statistical framework, we identified microsatellite mutations that were predictive of MSI within and across cancer types. The diagnostic accuracy of different subsets of maximally informative markers was estimated computationally using a dedicated validation set. Results Twenty-five cancer types exhibited hypermutated states consistent with MSI. Recurrently mutated microsatellites associated with MSI were identifiable in 15 cancer types, but were largely specific to individual cancer types. Cancer-specific microsatellite panels of 1 to 7 loci were needed to attain ≥95% diagnostic sensitivity and specificity for 11 cancer types, and in 8 of the cancer types, 100% sensitivity and specificity were achieved. Breast cancer required 800 loci to achieve comparable performance. We were unable to identify recurrent microsatellite mutations supporting reliable MSI diagnosis in ovarian tumors. Features associated with informative microsatellites were cataloged. Conclusions Most microsatellites informative for MSI are specific to particular cancer types, requiring the use of tissue-specific loci for optimal diagnosis. Limited numbers of markers are needed to provide accurate MSI diagnosis in most tumor types, but it is challenging to diagnose breast and ovarian cancers using predefined microsatellite locus panels.
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Wang, Ying, Ming Kang y Hongwen Huang. "Microsatellite Loci Transferability in Chestnut". Journal of the American Society for Horticultural Science 133, n.º 5 (septiembre de 2008): 692–700. http://dx.doi.org/10.21273/jashs.133.5.692.
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Cross-species amplification of 55 microsatellite loci developed in european chestnut (Castanea sativa Mill.) and japanese chestnut (C. crenata Sieb & Zucc.) was tested in three chestnut species from China [C. mollissima Blume, C. seguinii Dode, and C. henryi (Skan.) Rehder & Wilson]. Among all the tested loci, 47 (85.5%), 47 (85.5%), and 44 (80%) were successfully amplified in each of the three Chinese species, respectively. All microsatellite loci tested from C. crenata successfully amplified in the Chinese species, while only 80.5%, 80.5%, and 73.2% of the loci originating from C. sativa amplified in the three Chinese species. The level of polymorphism and mean number of alleles was 58.2% and 4.12 for C. mollissima, 60% and 4.64 for C. seguinii, and 60% and 4.76 for C. henryi, with mean observed heterozygosity ranging from 0.440 to 0.549 and mean expected heterozygosity ranging from 0.506 to 0.615. Transferability of Castanea Mill. microsatellites provides a powerful tool for chestnut breeding programs and conservation genetic studies of Castanea species.
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McConnell, Stewart K., Patrick O'Reilly, Lorraine Hamilton, Jonathan M. Wright y Paul Bentzen. "Polymorphic microsatellite loci from Atlantic salmon (Salmo salar): genetic differentiation of North American and European populations". Canadian Journal of Fisheries and Aquatic Sciences 52, n.º 9 (1 de septiembre de 1995): 1863–72. http://dx.doi.org/10.1139/f95-779.
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Atlantic salmon populations show low levels of genetic differentiation relative to other salmonid species, when surveyed by allozymes, and with mitochondrial DNA and nuclear ribosomal DNA markers. Here we report the application of three novel microsatellite VNTR loci to population differentiation in Atlantic salmon. A total of 232 microsatellites, cloned from Atlantic salmon, were classified as perfect, imperfect, and compound repeats. Microsatellite length, as in other teleosts, was significantly larger than published mammalian microsatellites. Primers for PCR amplification of three salmon microsatellites were designed. Allele frequencies, degree of polymorphism, and heterozygosity were estimated for five populations from Nova Scotia, Canada, and from Europe. Nei's genetic distances of 0.02–0.9 were observed among populations. There was a clear discrimination between Canadian and European fish based on unique alleles present at two loci. These Atlantic salmon primers also amplify presumably homologous loci in nine other salmonid species. The polymorphic microsatellites loci reported here demonstrate great potential as genetic markers in population, breeding, and evolutionary studies.
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Ling, Chen, Wu Lixia, Hou Rong, Shen Fujun, Zhang Wenping, Tang Yao, Yuan Yaohua, Zhao Bo y Zhang Liang. "Comparative analysis of microsatellite and SNP markers for parentage testing in the golden snub-nosed monkey (Rhinopithecus roxellana)". Conservation Genetics Resources 12, n.º 4 (3 de abril de 2020): 611–20. http://dx.doi.org/10.1007/s12686-020-01147-7.
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Abstract Microsatellite markers are popular for assigning parentage, but single-nucleotide polymorphisms (SNPs) have only been applied in this area recently. To evaluate these two markers which have been previously studied in golden snub-nosed monkeys, we genotyped 12 individuals using 37 microsatellite loci and 37 SNP markers. The data showed that 32 of 37 microsatellite loci were polymorphic, and most microsatellite loci were high informative (mean PIC = 0.599). Meanwhile, 24 of 37 SNP markers were polymorphic and most were low informative (mean PIC = 0.244). For microsatellites, the combined exclusion probability with one-parent-unknown/known (CE-1P/CE-2P) nearly reached 1, while for the SNP markers, CE-2P only reached 0.9582. Under the condition of one parent known/unknown, the CE-2P and CE-1P could meet the international human parental standard (0.9973) by using five or nine microsatellite loci respectively. For SNP markers, we doubled the loci (n = 48) and simulated parentage testing, and the data showed that the CE-2P was 0.998 while the CE-1P was still low. This result indicated that the SNP loci which we used here had low polymorphism and that more loci need to be developed in the future. In addition, we corrected one case of failed identification by excluding siblings and reducing the range of candidate paternities.
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Rossetto, M., F. C. L. Harriss, A. Mclauchlan, R. J. Henry, P. R. Baverstock y L. S. Lee. "Interspecific amplification of tea tree (Melaleuca alternifolia-Myrtaceae) microsatellite loci-potential implications for conservation studies". Australian Journal of Botany 48, n.º 3 (2000): 367. http://dx.doi.org/10.1071/bt98084.
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This study investigated the interspecific amplification of 35 microsatellite loci developed for M. alternifolia across seven other species within the Myrtaceae. All the primers used gave successful amplification of loci in at least one of the species tested. The level of success varied between species; 88.6% of primers gave amplification products for Melaleuca spp., 74.3% for Callistemon salignus, 45.7% for Eucalyptus spp. and 25.7% for Backhousia citriodora. Sequencing of a number of amplification products confirmed the presence of microsatellites in those loci. This study shows that the development of species-specific microsatellite libraries might not always be necessary. Cross-species amplification could enable the application of microsatellite technology to studies with limited resources, a feature characteristic of conservation projects.
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Thiéry, M. y D. Mugniéry. "Microsatellite loci in the phytoparasitic nematode Globodera". Genome 43, n.º 1 (1 de febrero de 2000): 160–65. http://dx.doi.org/10.1139/g99-106.
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A Globodera pallida genomic library, population Guiclan (Pa2/3), was screened for TG and TC microsatellite motifs. Screening of 50 000 clones revealed 48 positive matches. After sequencing, primers were designed to amplify 14 microsatellite loci. The specificity of the loci was tested with DNA templates of other populations of G. pallida, and also on other species of Globodera. Appearance of amplification products on several of these DNA templates showed that the microsatellite flanking regions are relatively conserved between G. pallida populations as well as between Globodera species. Evidence for allele polymorphism between individuals was demonstrated by using nine loci primers, in G. pallida population Guiclan and from a population of a closely related species G. "mexicana". Some alleles appeared to be species specific. Key words: Globodera, microsatellites, nematodes, phytoparasite, allele frequency.
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Feng, Xiaochuan, Stephen M. Rich, Donna Akiyoshi, James K. Tumwine, Addy Kekitiinwa, Nicolette Nabukeera, Saul Tzipori y Giovanni Widmer. "Extensive Polymorphism in Cryptosporidium parvumIdentified by Multilocus Microsatellite Analysis". Applied and Environmental Microbiology 66, n.º 8 (1 de agosto de 2000): 3344–49. http://dx.doi.org/10.1128/aem.66.8.3344-3349.2000.
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ABSTRACT Restriction fragment length polymorphism and DNA sequence analysis discern two main types of Cryptosporidium parvum. We present a survey of length polymorphism at several microsatellite loci for type 1 and type 2 isolates. A total of 14 microsatellite loci were identified from C. parvum DNA sequences deposited in public databases. All repeats were mono-, di-, and trinucleotide repeats of A, AT, and AAT, reflecting the high AT content of the C. parvum genome. Several of these loci showed significant length polymorphism, with as many as seven alleles identified for a single locus. Differences between alleles ranged from 1 to 27 bp. Karyotype analysis using probes flanking three microsatellites localized each marker to an individual chromosomal band, suggesting that these markers are single copy. In a sample of 19 isolates for which at least three microsatellites were typed, a majority of isolates displayed a unique multilocus fingerprint. Microsatellite analysis of isolates passaged between different host species identified genotypic changes consistent with changes in parasite populations.
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Gouin, Nicolas, Scott J. Westenberger, Susan M. Mahaney, Peter Lindley, John L. VandeBerg y Paul B. Samollow. "Development, inheritance, and linkage-group assignment of 60 novel microsatellite markers for the gray, short-tailed opossum Monodelphis domestica". Genome 48, n.º 6 (1 de diciembre de 2005): 1019–27. http://dx.doi.org/10.1139/g05-059.
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Short-tandem-repeat (SSR) or microsatellite polymorphisms are some of the most extensively employed genetic markers in contemporary linkage mapping studies. To date, only a limited number of microsatellites have been isolated in the gray, short-tailed opossum Monodelphis domestica, a South American marsupial widely used for comparative biological and biomedical research. To increase the number of potentially useful mapping markers, we screened 2 microsatellite-enriched genomic libraries containing alternatively (CA)n or (GA)n repeats. A total of 184 clones were sequenced, from which 60 polymorphic microsatellite markers were successfully optimized. The efficiency of this enrichment protocol for M. domestica microsatellite isolation is discussed, and suggestions to improve the outcome are made. All 60 loci showed high allelic diversity, with allele numbers ranging from 2 to 10 in a subset of 33 unrelated animals. Normal Mendelian inheritance was confirmed for all loci by analyzing allelic segregation in 5 two-generation families. One microsatellite appeared to be X linked, and null alleles were found in 5 others. Two-point linkage analyses were implemented using the data on the 5 families, leading to the assignment of 59 of these loci to the existing linkage groups. The 60 novel microsatellites developed in this study will contribute significantly to the M. domestica linkage map, and further QTL mapping studies.Key words: Monodelphis domestica, marsupial, microsatellite, enriched libraries, genetic linkage analysis.
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Rahman, Muhammad H., S. Dayanandan y Om P. Rajora. "Microsatellite DNA markers in Populus tremuloides". Genome 43, n.º 2 (15 de marzo de 2000): 293–97. http://dx.doi.org/10.1139/g99-134.
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Markers for eight new microsatellite DNA or simple sequence repeat (SSR) loci were developed and characterized in trembling aspen (Populus tremuloides) from a partial genomic library. Informativeness of these microsatellite DNA markers was examined by determining polymorphisms in 38 P. tremuloides individuals. Inheritance of selected markers was tested in progenies of controlled crosses. Six characterized SSR loci were of dinucleotide repeats (two perfect and four imperfect), and one each of trinucleotide and tetranucleotide repeats. The monomorphic SSR locus (PTR15) was of a compound imperfect dinucleotide repeat. The primers of one highly polymorphic SSR locus (PTR7) amplified two loci, and alleles could not be assigned to a specific locus. At the other six polymorphic loci, 25 alleles were detected in 38 P. tremuloides individuals; the number of alleles ranged from 2 to 7, with an average of 4.2 alleles per locus, and the observed heterozygosity ranged from 0.05 to 0.61, with an average of 0.36 per locus. The two perfect dinucleotide and one trinucleotide microsatellite DNA loci were the most informative. Microsatellite DNA variants of four SSR loci characterized previously followed a single-locus Mendelian inheritance pattern, whereas those of PTR7 from the present study showed a two-locus Mendelian inheritance pattern in controlled crosses. The microsatellite DNA markers developed and reported here could be used for assisting various genetic, breeding, biotechnology, genome mapping, conservation, and sustainable forest management programs in poplars. Key words: poplar, microsatellites, genetic mapping, simple sequence repeat (SSR) markers, DNA fingerprinting.
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Tanck, M. WT, A. P. Palstra, M. van de Weerd, C. P. Leffering, JJ van der Poel, H. Bovenhuis y J. Komen. "Segregation of microsatellite alleles and residual heterozygosity at single loci in homozygous androgenetic common carp (Cyprinus carpio L.)". Genome 44, n.º 5 (1 de octubre de 2001): 743–51. http://dx.doi.org/10.1139/g01-072.
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Thirty-three androgenetic progeny groups of common carp were analysed using 11 microsatellite markers to (i) verify the homozygous status of the 566 androgenetic individuals, (ii) analyse the microsatellite allele segregation, and (iii) study the possible association of microsatellite alleles with phenotypic traits. In total, 92% of the androgenetic individuals proved to be homozygous at all 11 loci. Forty-three of the 47 heterozygous individuals were heterozygous at a single locus only. This heterozygosity was probably due to DNA fragments caused by UV irradiation of the eggs, although the maternal origin of the fragments could not be proved beyond doubt. Screening with 11 microsatellites also revealed two linkage groups, a segregation distortion at two microsatellite loci, and the possible association of some microsatellites with mass, length, stress-related plasma cortisol levels, and basal plasma glucose levels. The success of the linkage and association study could be explained by a low recombination frequency due to high chiasma interference. This would imply a relatively short genetic map for common carp.Key words: doubled haploids, residual heterozygosity, microsatellite allele segregation, linkage analysis, common carp.
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WILDER, J. A., T. DIAZ, R. J. W. O'NEILL, J. KENNEY y H. HOLLOCHER. "Characterization and isolation of novel microsatellites from the Drosophila dunni subgroup". Genetical Research 80, n.º 3 (diciembre de 2002): 177–85. http://dx.doi.org/10.1017/s0016672302005864.
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We have isolated and characterized 77 novel microsatellites from two species, Drosophila dunni and Drosophila nigrodunni, which are closely related Caribbean-island endemics from the Drosophila cardini species group. These species are very distantly related to all other Drosophila from which microsatellites have previously been characterized. We find that the average length of microsatellites isolated in these species is quite small, with an overall mean length of 9·8 repeat units for dinucleotide microsatellites in the two study species. The nucleotide composition of dinucleotides differs between the two species: D. nigrodunni has a predominance of (AC/GT)n repeats, whereas D. dunni has equal numbers of (AC/GT)n and (AG/CT)n repeats. Tri- and tetranucleotide repeats are not abundant in either species. We assayed the variability of eight microsatellites in a closely related third species, Drosophila arawakana, using wild-caught individuals from the island of Guadeloupe. We found the microsatellites to be extremely variable in this population, with observed heterozygosities ranging from 0·541 to 0·889. DNA amplification trials suggest that these eight microsatellites are widely conserved across the D. cardini group, with five of the eight producing amplification products in every species tested. However, the loci are very poorly conserved over greater phylogenetic distances. DNA amplification of the microsatellite loci was unreliable in members of the closely related Drosophila quinaria, Drosophila calloptera, Drosophila guarani and Drosophila tripunctata species groups. Furthermore, these microsatellites could not be detected in the genome of Drosophila melanogaster, despite the conservation of microsatellite flanking regions at some loci. These data indicate that Drosophila microsatellite loci are quite short lived over evolutionary timescales relative to many other taxa.
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Zhang, Li-Fang, Shan-Geng He y Xiao-Long Li. "The Characteristics of Microsatellites and Development of SSR Markers in the Genome of Periplaneta americana". Journal of Biobased Materials and Bioenergy 18, n.º 5 (1 de octubre de 2024): 956–66. http://dx.doi.org/10.1166/jbmb.2024.2444.
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The research was to analyze the number and pattern of microsatellites in Periplaneta americana’s genome, and also developed tetranucleotide SSR markers. We thoroughly scrutinized and dissected the inherent traits that govern the allocation of microsatellite sequences within the profound domain of P. americana’s genome, software MSDBv2 allowed for the utilization of 2.67 Gb. There were precisely 1,498,458 flawless microsatellite sequences, encompassed approximately 1.57%. The cumulative length of microsatellites was 45,076,707 bp, and the abundance of microsatellites was 16889.577 loci/Mb. Out of all the microsatellite repeat variations, the trinucleotide repeats accounted for 44.83% of the total, with a count of 671,830, which were the most abundant type. The tetranucleotide, mononucleotide, pentanucleotide, dinucleotide, and hexanucleotide repeats accounted for 29.01%, 13.62%, 8.37%, 3.70% and 0.47%, respectively. The numbers of different repeat copy categories in each repeat type were also quite different, such as the A in mononucleotide repeat type, the AT in dinucleotides, the AAT in trinucleotides, and AAAT in tetranucleotide were the most of each categories. 143 primers were designed. After undertaking the arduous task of enhancing the initial PCR conditions to perfection, we successfully determined and analyzed a gargantuan number of 38 different polymorphic tetranucleotide microsatellite markers with utmost precision, employed the assistance of two-color fluorescence markers and ingenious genotyping scaned for their comprehensive characterization. The genetic variation in P. americana population involved analyzing the diversity of microsatellite loci, which exhibited varying numbers of alleles per locus ranging from 4 to 21 among the 32 individuals studied. Among them, there were 24 microsatellite loci whose alleles were greater than 10, accounted for 63.16% of the total number of polymorphic microsatellite. The calculated degrees of genetic diversity varied between 0 and 1, the observed heterozygosities was between 0.219 and 1.0, with a mean of 0.6391. The expected heterozygosities was between 0.312 and 0.942, with a mean of 0.7663. The PIC was between 0.296 and 0.923, with a mean of 0.7294, and there were 36 microsatellite loci whose PIC was greater than 0.5, accounted for 94.74%. This study indicated that new development of microsatellite markers for P. americana was feasible. Furthermore, these new development microsatellite markers will provide adequate and reliable molecular genetics data for carrying out the research of molecular ecology and conservation genetics for P. americana.
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Gaffney, Patrick M., Carita M. Pascal, Jeffery Barnhart, W. Stewart Grant y James E. Seeb. "Genetic homogeneity of weathervane scallops (Patinopecten caurinus) in the northeastern Pacific". Canadian Journal of Fisheries and Aquatic Sciences 67, n.º 11 (noviembre de 2010): 1827–39. http://dx.doi.org/10.1139/f10-096.
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We assessed genetic differentiation among populations of weathervane scallop ( Patinopecten caurinus ) in the northeastern Pacific, extending over 2500 km in the Gulf of Alaska and southeastern Bering Sea. Variability was surveyed at nuclear loci with allozyme, microsatellite, and single nucleotide polymorphism (SNP) methods, and at mitochondrial (mt)DNA loci with SNPs and nucleotide sequencing. High levels of gene diversity were detected for allozymes (H = 0.080), microsatellites (H = 0.734), and mtDNA (h = 0.781). Genotypes at nuclear loci generally fit Hardy–Weinberg proportions, except for some microsatellite loci, for which null-allele frequencies of 0.02 to 0.34 were estimated. No allele-frequency differences were detected among samples, except for the allozyme loci Gpi and Pep-4. Overall levels of differentiation ranged from FST = 0.0004 for allozymes, FST = 0.0008 for mtDNA to FST = 0.0004 for microsatellites. No isolation by distance was found for any of the markers. A unimodal mtDNA mismatch distribution and significant excesses of low-frequency variants for allozymes, microsatellites, and mtDNA may reflect a post-glacial population expansion. The lack of genetic differentiation measured by neutral markers does not preclude the existence of locally adapted, self-sustaining populations that are important in the harvest management of this species.
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Boches, Peter, Lisa J. Rowland, Kim Hummer y Nahla V. Bassil. "Microsatellite Markers Developed from `Bluecrop' Reveal Polymorphisms in the Genus Vaccinium and Are Suitable for Cultivar Fingerprinting". HortScience 40, n.º 4 (julio de 2005): 1122B—1122. http://dx.doi.org/10.21273/hortsci.40.4.1122b.
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Microsatellite markers for blueberry (Vaccinium L.) were created from a preexisting blueberry expressed sequence tag (EST) library of 1305 sequences and a microsatellite-enriched genomic library of 136 clones. Microsatellite primers for 65 EST-containing simple sequence repeats (SSRs) and 29 genomic SSR were initially tested for amplification and polymorphism on agarose gels. Potential usefulness of these SSRs for estimating species relationships in the genus was assessed through cross-species transference of 45 SSR loci and cluster analysis using genetic distance values from five highly polymorphic EST-SSR loci. Cross-species amplification for 45 SSR loci ranged from 17% to 100%, and was 83% on average in nine sections. Cluster analysis of 59 Vaccinium species based on genetic distance measures obtained from 5 EST-SSR loci supported the concept of V. elliotii Chapm. as a genetically distinct diploid highbush species and indicated that V. ashei Reade is of hybrid origin. Twenty EST-SSR and 10 genomic microsatellite loci were used to determine genetic diversity in 72 tetraploid V. corymbosum L. accessions consisting mostly of common cultivars. Unique fingerprints were obtained for all accessions analyzed. Genetic relationships, based on microsatellites, corresponded well with known pedigree information. Most modern cultivars clustered closely together, but southern highbush and northern highbush cultivars were sufficiently differentiated to form distinct clusters. Future use of microsatellites in Vaccinium will help resolve species relationships in the genus, estimate genetic diversity in the National Clonal Germplasm Repository (NCGR) collection, and confirm the identity of clonal germplasm accessions.
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Harr, Bettina y Christian Schlötterer. "Long Microsatellite Alleles in Drosophila melanogaster Have a Downward Mutation Bias and Short Persistence Times, Which Cause Their Genome-Wide Underrepresentation". Genetics 155, n.º 3 (1 de julio de 2000): 1213–20. http://dx.doi.org/10.1093/genetics/155.3.1213.
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Abstract Microsatellites are short tandemly repeated DNA sequence motifs that are highly variable in most organisms. In contrast to mammals, long microsatellites (>15 repeats) are extremely rare in the Drosophila melanogaster genome. To investigate this paucity of long microsatellites in Drosophila, we studied 19 loci with exceptionally long microsatellite alleles. Inter- and intraspecific analysis showed that long microsatellite alleles arose in D. melanogaster only very recently. This lack of old alleles with many repeats indicated that long microsatellite alleles have short persistence times. The size distribution of microsatellite mutations in mutation-accumulation lines suggests that long alleles have a mutation bias toward a reduction in the number of repeat units. This bias causes the short persistence times of long microsatellite alleles. We propose that species-specific, size-dependent mutation spectra of microsatellite alleles may provide a general mechanism to account for the observed differences in microsatellite length between species.
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Rivero-Hinojosa, Samuel, Nicholas Kinney, Harold R. Garner y Brian R. Rood. "Germline microsatellite genotypes differentiate children with medulloblastoma". Neuro-Oncology 22, n.º 1 (28 de septiembre de 2019): 152–62. http://dx.doi.org/10.1093/neuonc/noz179.
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Abstract Background The germline genetic events underpinning medulloblastoma (MB) initiation, and therefore the ability to determine who is at risk, are still unknown for the majority of cases. Microsatellites are short repeated sequences that make up ~3% of the genome. Repeat lengths vary among individuals and are often nonrandomly associated with disease, including several cancers such as breast, glioma, lung, and ovarian. Due to their effects on gene function, they have been called the “tuning knobs of the genome.” Methods We have developed a novel approach for identifying a microsatellite-based signature to differentiate MB patients from controls using germline DNA. Results Analyzing germline whole exome sequencing data from a training set of 120 MB subjects and 425 controls, we identified 139 individual microsatellite loci whose genotypes differ significantly between the groups. Using a genetic algorithm, we identified a subset of 43 microsatellites that distinguish MB subjects from controls with a sensitivity and specificity of 92% and 88%, respectively. This microsatellite signature was validated in an independent dataset consisting of 102 subjects and 428 controls, with comparable sensitivity and specificity of 95% and 90%, respectively. Analysis of the allele genotypes of those 139 informative loci demonstrates that their association with MB is a consequence of individual microsatellites' genotypes rather than their hypermutability. Finally, an analysis of the genes harboring these microsatellite loci reveals cellular functions important for tumorigenesis. Conclusion This study demonstrates that MB-specific germline microsatellite variations mark those at risk for MB development and suggests mechanisms of predisposition.
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Douek, Jacob, Elad Nehoray Rachmilovitz y Baruch Rinkevich. "New Microsatellite Markers for the Model Coral Species Stylophora pistillata from Eilat, the Red Sea". Journal of Marine Science and Engineering 11, n.º 2 (18 de enero de 2023): 244. http://dx.doi.org/10.3390/jmse11020244.
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Nineteen microsatellite loci, obtained by the whole genome sequencing approach, were developed and validated for the ‘smooth cauliflower’ coral Stylophora pistillata, a widespread Indo Pacific branching coral species. A sample size of 40 colonies collected at five reef sites along the northern Gulf of Eilat, the Red Sea, were genotyped, revealing loci reproducibly and suitable outcomes for wide applications, including population genetic studies. The 19 new microsatellite loci in this sample were composed of 4–20 alleles/locus, of which 10 microsatellites are highly polymorphic (≥10 alleles/locus). The observed and expected heterozygosity ranged between 0.289 and 0.957 (mean 0.597) and 0.101 and 0.911 (mean 0.726), respectively, and the Fixation Index (F), which also indicates the inbreeding coefficient, ranges between −0.174 and 0.569 (mean 0.207). The polymorphic information content (PIC) ranges between 0.100 and 0.904 (mean 0.699). This new set of microsatellite loci will be employed for population genetics studies as for identifying the distribution of various genotypes within S. pistillata chimeras.
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Reddy, K. Damodar, E. G. Abraham y J. Nagaraju. "Microsatellites in the silkworm, Bombyx mori: Abundance, polymorphism, and strain characterization". Genome 42, n.º 6 (1 de diciembre de 1999): 1057–65. http://dx.doi.org/10.1139/g99-027.
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We have isolated and characterized microsatellites (simple sequence repeat (SSR) loci) from the silkworm genome. The screening of a partial genomic library by the conventional hybridization method led to the isolation of 28 microsatellites harbouring clones. The abundance of (CA)n repeats in the silkworm genome was akin to those reported in the other organisms such as honey bee, pig, and human, but the (CT)n repeat motif is less common compared to bumble bee and honey bee genomes. Detailed analysis of 13 diverse silkworm strains with a representative of 15 microsatellite loci revealed a number of alleles ranging from 3 to 17 with heterozygosity values of 0.66-0.90. Along with strain-specific microsatellite markers, diapause and non-diapause strain-specific alleles were also identified. The repeat length did not show any relationship with the degree of polymorphism in the present study. The co-dominant inheritance of microsatellite markers was demonstrated in F1 offspring. A list of primer sequences that tag each locus is provided. The availability of microsatellite markers can be expected to enhance the power and resolution of genome analysis in silkworm.Key words: microsatellites, simple sequence repeats, polymorphisms, silkworm strains, Bombyx mori.
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Korom, E., K. Bakos, G. Veress, O. Pinke, K. M. Reed, L. Varga y B. Kovács. "Isolation of 11 new polymorphic microsatellites from CA enriched turkey genomic libraries (Short communication)". Archives Animal Breeding 53, n.º 5 (10 de octubre de 2010): 618–22. http://dx.doi.org/10.5194/aab-53-618-2010.
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Abstract. Microsatellite loci from the ancient Hungarian variety of the Broad Breasted Bronze Turkey (Meleagris gallopavo) were isolated. CA-repeat enriched libraries were constructed from DNA of randomly collected samples. Libraries were screened for repeat-containing clones by PIMA (PCR Isolation of Microsatellite Arrays) and the DNA-sequence of 167 positive clones was determined. A total of 136 microsatellite repeat-containing sequences were found, 59 sequences were unique. Comparing these with the genomic databases, we found 7 previously annotated microsatellite sequences. The newly isolated 52 microsatellites were tested on the mapping population of the University of Minnesota, and the map position of 11 microsatellites was determined.
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Akiyama, S., T. Grant, N. J. Gemmell, J. A. Marshall-Graves y N. D. Murray. "Microsatellite Loci and Population Structure in the Platypus." Australian Mammalogy 20, n.º 2 (1998): 299. http://dx.doi.org/10.1071/am98298.
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To investigate the genetic relationships within and between platypus populations, molecular genetic methods employing DNA analysis are very effective, and microsatellite variation has been shown to be the most effective for population studies. Microsatellites are segments of DNA with tandem repeats of short sequence motifs, usually 1-6 base pairs of nucleotides, and they are highly variable and easy to score. Several microsatellite loci have been detected and sequenced, and PCR primers have been constructed and used to identify several polymorphic microsatellite variants. In the main breeding population, from which we have a collection of over 80 animals, two alleles not found among resident or other captured males were detected amongst juveniles. From our combination of microsatellite and mtDNA analysis, these alleles are likely to be derived from uncaptured transient males which participated in breeding. We therefore suggest that the mating system in this population of platypus involves polygyny and sneaking. Allele frequency differences have been detected between sub-populations within the same stream, consistent with observations on mtDNA genotypes. As well, there are allele frequency differences between populations from different streams and these show continuous geographical gradation, consistent with an isolation-by-distance geographical structure.
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Smith, S., T. Joss y A. Stow. "Successful development of microsatellite markers in a challenging species: the horizontal borer Austroplatypus incompertus (Coleoptera: Curculionidae)". Bulletin of Entomological Research 101, n.º 5 (11 de abril de 2011): 551–55. http://dx.doi.org/10.1017/s0007485311000137.
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AbstractThe analysis of microsatellite loci has allowed significant advances in evolutionary biology and pest management. However, until very recently, the potential benefits have been compromised by the high costs of developing these neutral markers. High-throughput sequencing provides a solution to this problem. We describe the development of 13 microsatellite markers for the eusocial ambrosia beetle, Austroplatypus incompertus, a significant pest of forests in southeast Australia. The frequency of microsatellite repeats in the genome of A. incompertus was determined to be low, and previous attempts at microsatellite isolation using a traditional genomic library were problematic. Here, we utilised two protocols, microsatellite-enriched genomic library construction and high-throughput 454 sequencing and characterised 13 loci which were polymorphic among 32 individuals. Numbers of alleles per locus ranged from 2 to 17, and observed and expected heterozygosities from 0.344 to 0.767 and from 0.507 to 0.860, respectively. These microsatellites have the resolution required to analyse fine-scale colony and population genetic structure. Our work demonstrates the utility of next-generation 454 sequencing as a method for rapid and cost-effective acquisition of microsatellites where other techniques have failed, or for taxa where marker development has historically been both complicated and expensive.
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Horreo, Jose Luis, Maria Luisa Peláez, Teresa Suárez, Benoit Heulin y Patrick Stefan Fitze. "Development of thirty-four new microsatellite loci and multiplexing of seven existing loci for Zootoca vivipara (Squamata: Lacertidae)". Phyllomedusa: Journal of Herpetology 16, n.º 1 (28 de junio de 2017): 89. http://dx.doi.org/10.11606/issn.2316-9079.v16i1p89-96.
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Few microsatellite loci exist for the European common lizard, Zootoca vivipara, a common model species in studies of population dynamics, sexual selection, population genetics, parity evolution, and physiology. The existing primers did not amplify in all lineages, and multiplexes were not optimized. A total of 34 new polymorphic microsatellite markers have been developed for this species and tested in 64 specimens belonging to oviparous and viviparous clades (B and D). The microsatellites were combined into seven different multiplexes. Results showed that all but one loci successfully amplified in all samples and both clades. The number of alleles detected per locus ranged 7–22 alleles and the effective number 1.58–7.82. The observed heterozygosity ranged 0.312–0.930, showing that all loci were highly variable. Oviparous and viviparous clades exhibited significant genetic differences (in FST). In addition to these new markers, the seven previously published and widely used microsatellite loci have been multiplexed and tested in oviparous clades. These innovations will allow for timesaving and robust analyses in Zootoca vivipara, boosting evolutionary and population studies and easing paternity analyses
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Harker, N., L. R. Rampling, M. R. Shariflou, M. J. Hayden, T. A. Holton, M. K. Morell, P. J. Sharp, R. J. Henry y K. J. Edwards. "Microsatellites as markers for Australian wheat improvement". Australian Journal of Agricultural Research 52, n.º 12 (2001): 1121. http://dx.doi.org/10.1071/ar01025.
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Microsatellite markers have been shown to be highly polymorphic and simple to use in hexaploid wheat. This study aimed to establish microsatellites as informative markers for Australian wheat improvement. By screening microsatellites developed as part of the Wheat Microsatellite Consortium and other available microsatellite sources, 257 informative microsatellites for Australian wheat varieties were identified and reported in the Australian National Wheat Molecular Marker Program microsatellite database (http://www.scu.edu.au/research/cpcg/). Of these, 151 microsatellites identifying 172 loci were scored on at least 1 of 4 double haploid mapping populations and were then integrated, where possible, into existing genetic maps. Polymorphism information content values were calculated for most microsatellites to establish a reference for their value for future investigations. The mapping of available microsatellites enhances the quality of the genetic maps and may provide useful genetic markers for traits of interest to the Australian wheat breeding programs.
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White, E., R. Sahota y S. Edes. "Rapid microsatellite analysis using discontinuous polyacrylamide gel electrophoresis". Genome 45, n.º 6 (1 de diciembre de 2002): 1107–9. http://dx.doi.org/10.1139/g02-084.
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A method for screening large numbers of samples for microsatellites using discontinuous, non-denaturing polyacrylamide gels and rapid fluorescent gel staining is described. Disc electrophoresis on slab gels provides high-resolution of PCR products. It is useful for collecting population data once microsatellite loci have been characterized.Key words: microsatellite, discontinuous polyacrylamide gel electrophoresis, non-denaturing
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Zhu, Ying, Hong-Yi Liu, Hai-Qiong Yang, Yu-Dong Li y He-Min Zhang. "Factors affecting genotyping success in giant panda fecal samples". PeerJ 5 (23 de mayo de 2017): e3358. http://dx.doi.org/10.7717/peerj.3358.
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Fecal samples play an important role in giant panda conservation studies. Optimal preservation conditions and choice of microsatellites for giant panda fecal samples have not been established. In this study, we evaluated the effect of four factors (namely, storage type (ethanol (EtOH), EtOH −20 °C, 2-step storage medium, DMSO/EDTA/Tris/salt buffer (DETs) and frozen at −20 °C), storage time (one, three and six months), fragment length, and repeat motif of microsatellite loci) on the success rate of microsatellite amplification, allelic dropout (ADO) and false allele (FA) rates from giant panda fecal samples. Amplification success and ADO rates differed between the storage types. Freezing was inferior to the other four storage methods based on the lowest average amplification success and the highest ADO rates (P < 0.05). The highest microsatellite amplification success was obtained from either EtOH or the 2-step storage medium at three storage time points. Storage time had a negative effect on the average amplification of microsatellites and samples stored in EtOH and the 2-step storage medium were more stable than the other three storage types. We only detected the effect of repeat motif on ADO and FA rates. The lower ADO and FA rates were obtained from tri- and tetra-nucleotide loci. We suggest that freezing should not be used for giant panda fecal preservation in microsatellite studies, and EtOH and the 2-step storage medium should be chosen on priority for long-term storage. We recommend candidate microsatellite loci with longer repeat motif to ensure greater genotyping success for giant panda fecal studies.
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Sumathi, Murugan y Yasodha Ramasamy. "Microsatellite allele length variations in inter-specific hybrids of Eucalyptus". Acta Botanica Croatica 76, n.º 1 (1 de marzo de 2017): 103–6. http://dx.doi.org/10.1515/botcro-2016-0050.
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AbstractThe genus Eucalyptus encompasses several species of industrial importance. Many of these species have been subjected to genetic characterization using different kinds of DNA markers. More than 1000 microsatellites have been identified from the genome of eucalypts and they are highly amenable for cross species transferability. During cross amplification of microsatellites, homoplasy is reported in many species in which although the allele size might be the same, the sequences are not. Thus, it is essential to ascertain the DNA sequence homology with source and target microsatellite repeats. Accordingly, fifty five alleles from six microsatellite loci (ECc1, ECc2, Eg61, Embra100, Embra1468 and Embra2002) were amplified in two inter-specific hybrid populations (Eucalyptus tereticornis × E. grandis and E. tereticornis × E. camaldulensis) and sequenced. The results showed that all the microsatellite loci were amplifying the target repeat types except for the loci Eg61 and Embra2002. The locus Eg61 has target repeat of (CAA)(GAT) but the sampled alleles had either (CAA)(GAT) or (GAT) alone. Similarly, the Embra2002 locus was targeting interrupting repeats of (CCA)..(CCA), but the sequenced alleles had repeats of (CCA) with or without interruption. Nevertheless, the allele size estimated in electrophoresis for hybrids was in conformity with that of the parent alleles. This study suggests the need for validation of the repeat characteristics of microsatellites by sequencing of the alleles particularly in cross species amplification.
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Hempel, K. y R. Peakall. "Cross-species amplification from crop soybean Glycine max provides informative microsatellite markers for the study of inbreeding wild relatives". Genome 46, n.º 3 (1 de junio de 2003): 382–93. http://dx.doi.org/10.1139/g03-013.
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The development of microsatellite markers through transfer of primers from related species (cross-species amplification) remains a little-explored alternative to the de novo method in plants. In this study of 100 microsatellite loci from Glycine max, we examined two aspects of primer transfer. First, we tested if source locus properties can predict primer transfer and polymorphism in Glycine cyrtoloba and Glycine clandestina. We transferred 23 primers to G. cyrtoloba and 42 to G. clandestina, with 19 loci polymorphic within G. clandestina. However, we could not predict transfer or polymorphism from the source locus properties. Second, we evaluated the subset of 11 polymorphic loci for study in G. clandestina populations representing two local morphotypes. All loci were informative within populations (population mean He ± SE = 0.58 ± 0.04). We directly sequenced 28 alleles at 4 representative loci. The allelic patterns and sequencing results established that 8 of 11 loci were typical microsatellites, confirming the utility of primer transfer as an alternative to de novo development. Additionally, we found that morphotypic differentiation between populations was paralleled by changes in polymorphism level at six loci and size homoplasy at one locus. We interpret these patterns as being a product of selfing in G. clandestina. Our results demonstrate the value of allele sequence knowledge for the most effective use of microsatellites.Key words: microsatellite transfer predictability, cross-species amplification, Glycine, selfing, size homoplasy.
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Rivera, R., K. J. Edwards, JHA Barker, G. M. Arnold, G. Ayad, T. Hodgkin y A. Karp. "Isolation and characterization of polymorphic microsatellites in Cocos nucifera L." Genome 42, n.º 4 (1 de agosto de 1999): 668–75. http://dx.doi.org/10.1139/g98-170.
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Microsatellites or simple sequence repeats (SSRs) were isolated from coconut (Cocos nucifera) and tested for polymorphism on restricted germplasm. Sequencing of 197 clones from a cv. Tagnanan Tall-enriched genomic library showed that 75% contained a microsatellite, of which 64% were dinucleotide (GA/CT, CA/GT and GC/CG), 6% were trinucleotide, and 30% were compound repeats. Of 41 primer pairs tested on Tagnanan Tall genomic DNA, 38 gave the expected size product, two amplified two loci, and another gave a multilocus pattern. On 20 coconut samples, the 38 SSRs detected 198 alleles (average: 5.2 alleles per microsatellite). Genetic diversity (D = 1 - Sigma pi2) values ranged from 0.141 to 0.809. Heterozygotes were present at high frequencies among some dwarf samples. Analysis of similarity matrices based either on shared alleles at each locus (simple matching coefficient) or on allele bands across all loci (Jaccard coefficient) showed similar results. Dwarfs grouped separately from talls and showed less genetic diversity. In a wider test on 40 samples, 8 SSRs detected 64 alleles (average: eight alleles per microsatellite). These results indicate the high potential of microsatellites to detect genetic diversity in coconut germplasm.Key words: molecular markers, microsatellite, SSR, Cocos nucifera, coconut.
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O'Connell, Michael, Roy G. Danzmann, Jean-Marie Cornuet, Jonathan M. Wright y Moira M. Ferguson. "Differentiation of rainbow trout (Oncorhynchus mykiss) populations in Lake Ontario and the evaluation of the stepwise mutation and infinite allele mutation models using microsatellite variability". Canadian Journal of Fisheries and Aquatic Sciences 54, n.º 6 (1 de junio de 1997): 1391–99. http://dx.doi.org/10.1139/f97-043.
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Microsatellites, comprising (GT)\dn6 n tandemly repeated arrays, were isolated from a size-selected genomic library of rainbow trout (Oncorhynchus mykiss) DNA. Primers were designed for five microsatellite loci, four of which were variable. Primers for two of these loci were used in conjunction with primers for three microsatellite loci from a related species, Salmo salar, to investigate patterns of differentiation in freshwater migratory populations of rainbow trout in Lake Ontario. The five loci used revealed high levels of polymorphism with heterozygosity estimates ranging from 0.740 to 0.956. Significant differences in allele frequencies among populations were observed for all loci. Heterozygosity and allele number values, at each locus for each population, were used to test two alternative mutation models, the infinite allele model (IAM) and the stepwise mutation model (SMM). The predictions of the IAM proved to be more accurate for the majority of the data and this model was used to calculate estimates of effective population size.
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Nauta, Maarten J. y Franz J. Weissing. "Constraints on Allele Size at Microsatellite Loci: Implications for Genetic Differentiation". Genetics 143, n.º 2 (1 de junio de 1996): 1021–32. http://dx.doi.org/10.1093/genetics/143.2.1021.
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Abstract Microsatellites are promising genetic markers for studying the demographic structure and phylogenetic history of populations. We present theoretical arguments indicating that the usefulness of microsatellite data for these purposes may be limited to a short time perspective and to relatively small populations. The evolution of selectively neutral markers is governed by the interaction of mutation and random genetic drift. Mutation pressure has the inherent tendency to shift different populations to the same distribution of alleles. Hence, mutation pressure is a homogenizing force, and population divergence is caused by random genetic drift. In case of allozymes or sequence data, the diversifying effect of drift is typically orders of magnitude larger than the homogenizing effect of mutation pressure. By a simple model, we demonstrate that the situation may be different for microsatellites where mutation rates are high and the range of alleles is limited. With the help of computer simulations, we investigate to what extent genetic distance measures applied to microsatellite data can nevertheless yield useful estimators for phylogenetic relationships or demographic parameters. We show that predictions based on microsatellite data are quite reliable in small populations, but that already in moderately sized populations the danger of misinterpretation is substantial.
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FAKHAR, M., M. H. MOTAZEDIAN, D. DALY, C. D. LOWE, S. J. KEMP y H. A. NOYES. "An integrated pipeline for the development of novel panels of mapped microsatellite markers for Leishmania donovani complex, Leishmania braziliensis and Leishmania major". Parasitology 135, n.º 5 (27 de marzo de 2008): 567–74. http://dx.doi.org/10.1017/s0031182008004186.
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SUMMARYA panel of microsatellites mapped to the Leishmania genome might make it possible to find associations between specific loci and phenotypic traits. To identify such loci, a Perl programme was written that scans the sequence of a genome and writes all loci containing microsatellites to a MySQL database. The programme was applied to the sequences of the L. braziliensis, L. infantum and L. major genomes. The database is publicly available over the internet: http://www.genomics.liv.ac.uk/tryps/resources.html ‘Microsatellite Locus Extractor’, and allows the selection of mapped microsatellites that meet user-defined criteria from a specified region of the selected genome. The website also incorporates a primer design pipeline that will design primers to amplify the selected loci. Using this pipeline 12 out of 17 primer sets designed against the L. infantum genome generated polymorphic PCR products. A tailed primer protocol was used to label all microsatellite primers with a single set of labelled primers. To avoid the culture of parasites prior to genotyping, sets of nested PCR primers were developed to amplify parasite DNA eluted from microscope slides. The limit of detection was approximately 1·6 parasite equivalents. However, only 6/56 DNA from slides stored at ambient temperature for over 6 months gave positive PCR results.
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Dong, Zhiguo, Xugan Wu, Xiaoying Li, Qingqi Zhang, Jiale Li y Binlun Yan. "Report of 14 novel microsatellites from the swimming crab Portunus trituberculatus (Miers, 1876) (Decapoda, Brachyura)". Crustaceana 87, n.º 1 (2014): 35–40. http://dx.doi.org/10.1163/15685403-00003270.
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The swimming crab, Portunus trituberculatus (Miers, 1876) is one of the most common edible marine crabs in East Asia. In this study, a multiple mixed probes hybridization method was used to isolate microsatellites to improve experimental efficiency and streamline the procedure. The mix of biotinylated probes included microsatellite GA, CA and CAT motifs. Fourteen novel polymorphic microsatellite loci were isolated and characterized from a wild population of P. trituberculatus. The number of alleles varied between three and nine, and the observed and expected heterozygosity at population level ranged from 0.542 to 1.000 and 0.616 to 0.851, respectively. Two loci, Ptr1 and Ptr3, significantly deviated from the Hardy-Weinberg equilibrium (). These informative microsatellite markers could be useful for future population genetic analyses and genome mapping studies in this species.
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Dermitzakis, Emmanouil T., Andrew G. Clark, Costas Batargias, Antonios Magoulas y Eleftherios Zouros. "Negative Covariance Suggests Mutation Bias in a Two-Locus Microsatellite System in the Fish Sparus aurata". Genetics 150, n.º 4 (1 de diciembre de 1998): 1567–75. http://dx.doi.org/10.1093/genetics/150.4.1567.
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Abstract Constraints on microsatellite length appear to vary in a species-specific manner. We know very little about the nature of these constraints and why they should vary among species. While surveying microsatellite variation in the Mediterranean gilthead sea bream, Sparus aurata, we discovered an unusual pattern of covariation between two closely linked microsatellite loci. One- and two-locus haplotypes were scored from PCR amplification products of each locus separately and both loci together. In a sample of 211 fish, there was a strong negative covariance in repeat number between the two loci, which suggests a mechanism that maintains the combined length below a constrained size. In addition, there were two clusters of the same combined haplotype length, one consisting of a long repeat array at one locus and a short array at the other and vice versa. We demonstrate that several models of biased mutation or natural selection, in theory, could generate this pattern of covariance. The common feature of all the models is the idea that tightly linked microsatellites do not evolve in complete independence, and that whatever size dependence there is to the process, it appears to “read” the combined size of the two loci.
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Stanisic, Ljubodrag, Vladimir Dimitrijevic, Predrag Simeunovic, Uros Glavinic, Biljana Jovanovic, Jevrosima Stevanovic y Zoran Stanimirovic. "Assessment of 17 microsatellite loci for their use in parentage verification and individual identification in the Balkan donkey breed". Genetika 49, n.º 1 (2017): 21–30. http://dx.doi.org/10.2298/gensr1701021s.
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The aim of this study was to assess a panel of 17 microsatellites for parentage verification and individual identification in the endangered Balkan donkey breed. Allele frequencies for 17 microsatellite loci (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HTG4, HTG6, HTG7, HTG10, HMS1, HMS2, HMS3, HMS6, HMS7, LEX3 and VHL20) were determined in a 77 unrelated Balkan donkeys. Three loci (ASB2, HMS1 and ASB17) proved to be unsuitable and had been excluded from the investigation. Analysis of the remaining 14 loci revealed varied levels of polymorphism (three to 12 alleles), while the total number of observed alleles was 118 with an average of 8.42 per locus. Average values of observed heterozygosity and polymorphic information content (PIC) were 0.712 and 0.650, respectively. Twelve out of 14 microsatellite markers were highly informative with PIC values higher than 0.5. Only four loci were in HWE (HMS2, HMS6, HMS7 and HTG6). The obtained value of combined power of exclusion (0.9999) confirms usefulness of this microsatellite panel for parentage verification, while the value of combined power of discrimination of 0.9941 clearly approves the reliability of the panel for individual identification in Balkan donkeys.
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Maughan, P. J., M. A. Saghai Maroof y G. R. Buss. "Microsatellite and amplified sequence length polymorphisms in cultivated and wild soybean". Genome 38, n.º 4 (1 de agosto de 1995): 715–23. http://dx.doi.org/10.1139/g95-090.
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The objectives of this study were to (i) assess the extent of genetic variation in soybean microsatellites (simple sequence repeats or SSRs), (ii) assay for amplified sequence length polymorphisms (ASLPs), and (iii) evaluate the usefulness of SSRs and ASLPs as genetic markers. Five microsatellites detected a total of 79 variants (alleles) in a sample of 94 accessions of wild (Glycine soja) and cultivated soybean (G. max). F2 segregation analysis of four of the five microsatellites identified these variants (alleles) with four loci located in independent linkage groups. The number of alleles per microsatellite locus ranged from 5 to 21; to our knowledge these are the largest numbers of alleles for single Mendelian loci reported in soybean. Allelic diversity for the SSR loci was greater in wild than in cultivated soybean. Overall, 43 more SSR alleles were detected in wild than in cultivated soybean. These results indicate that SSRs are the marker of choice, especially for species with low levels of variation as detected by other types of markers. Two alleles were detected at each of the three ASLP loci examined. A total of six ASLP alleles were observed in cultivated soybean and five were observed in wild soybean; all alleles detected in wild soybean were present in cultivated soybean. Allelic diversity values for the ASLP loci were near previous estimates for restriction fragment length polymorphisms and therefore ASLPs may be useful as genetic markers in site-directed mapping.Key words: microsatellite, simple sequence repeat, soybean, amplified sequence length polymorphism, genetic mapping.
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Xu, Zhenkang, Laura Gutierrez, Matthew Hitchens, Steve Scherer, Amy K. Sater y Dan E. Wells. "Distribution of Polymorphic and Non-Polymorphic Microsatellite Repeats in Xenopus tropicalis". Bioinformatics and Biology Insights 2 (enero de 2008): BBI.S561. http://dx.doi.org/10.4137/bbi.s561.
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The results of our bioinformatics analysis have found over 91,000 di-, tri-, and tetranucleotide microsatellites in our survey of 25% of the X. tropicalis genome, suggesting there may be over 360,000 within the entire genome. Within the X. tropicalis genome, dinucleotide (78.7%) microsatellites vastly out numbered tri- and tetranucleotide microsatellites. Similarly, AT-rich repeats are overwhelmingly dominant. The four AT-only motifs (AT, AAT, AAAT, and AATT) account for 51,858 out of 91,304 microsatellites found. Individually, AT microsatellites were the most common repeat found, representing over half of all di-, tri-, and tetranucleotide microsatellites. This contrasts with data from other studies, which show that AC is the most frequent microsatellite in vertebrate genomes (Toth et al. 2000). In addition, we have determined the rate of polymorphism for 5,128 non-redundant microsatellites, embedded in unique sequences. Interestingly, this subgroup of microsatellites was determined to have significantly longer repeats than genomic microsatellites as a whole. In addition, microsatellite loci with tandem repeat lengths more than 30 bp exhibited a significantly higher degree of polymorphism than other loci. Pairwise comparisons show that tetranucleotide microsatellites have the highest polymorphic rates. In addition, AAT and ATC showed significant higher polymorphism than other trinucleotide microsatellites, while AGAT and AAAG were significantly more polymorphic than other tetranucleotide microsatellites.
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Tian, Ruizheng, Cunhuan Zhang, Yixiao Huang, Xin Guo y Maohua Chen. "A Novel Software and Method for the Efficient Development of Polymorphic SSR Loci Based on Transcriptome Data". Genes 10, n.º 11 (11 de noviembre de 2019): 917. http://dx.doi.org/10.3390/genes10110917.
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Traditional methods for developing polymorphic microsatellite loci without reference sequences are time-consuming and labor-intensive, and the polymorphisms of simple sequence repeat (SSR) loci developed from expressed sequence tag (EST) databases are generally poor. To address this issue, in this study, we developed a new software (PSSRdt) and established an effective method for directly obtaining polymorphism details of SSR loci by analyzing diverse transcriptome data. The new method includes three steps, raw data processing, PSSRdt application, and loci extraction and verification. To test the practicality of the method, we successfully obtained 1940 potential polymorphic SSRs from the transcript dataset combined with 44 pea aphid transcriptomes. Fifty-two SSR loci obtained by the new method were selected for validating the polymorphic characteristics by genotyping in pea aphid individuals. The results showed that over 92% of SSR loci were polymorphic and 73.1% of loci were highly polymorphic. Our new software and method provide an innovative approach to microsatellite development based on RNA-seq data, and open a new path for the rapid mining of numerous loci with polymorphism to add to the body of research on microsatellites.
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Vidakovic, D. O., D. Perovic, T. V. Semilet, A. Börner y E. K. Khlestkina. "The consensus rye microsatellite map with EST-SSRs transferred from wheat". Vavilov Journal of Genetics and Breeding 24, n.º 5 (28 de agosto de 2020): 459–64. http://dx.doi.org/10.18699/vj20.48-o.
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Microsatellite (SSR) markers with known precise intrachromosomal locations are widely used for mapping genes in rye and for the investigation of wheat-rye translocation lines and triticale highly demanded for mapping economically important genes and QTL-analysis. One of the sources of novel SSR markers in rye are microsatellites transferable from the wheat genome. Broadening the list of available SSRs in rye mapped to chromosomes is still needed, since some rye chromosome maps still have just a few microsatellite loci mapped. The goal of the current study was to integrate wheat EST-SSRs into the existing rye genetic maps and to construct a consensus rye microsatellite map. Four rye mapping populations (P87/P105, N6/N2, N7/N2 and N7/N6) were tested with CFE (EST-SSRs) primers. A total of 23 Xcfe loci were mapped on rye chromosomes: Xcfe023, -136 and -266 on chromosome 1R, Xcfe006, -067, -175 and -187 on 2R, Xcfe029 and -282 on 3R, Xcfe004, -100, -152, -224 and -260 on 4R, Xcfe037, -208 and -270 on 5R, Xcfe124, -159 and -277 on 6R, Xcfe010, -143 and -228 on 7R. With the exception of Xcfe159 and Xcfe224, all the Xcfe loci mapped were found in orthologous positions considering multiple evolutionary translocations in the rye genome relative to those of common wheat. The consensus map was constructed using mapping data from the four bi-parental populations. It contains a total of 123 microsatellites, 12 SNPs, 118 RFLPs and 2 isozyme loci.
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Biancalana, Renata Neves, Fabio Raposo do Amaral y Cibele Biondo. "Novel microsatellites for Cypseloides fumigatus, cross-amplifiable in Streptoprocne zonaris". Revista Brasileira de Ornitologia 27, n.º 3 (septiembre de 2019): 207–11. http://dx.doi.org/10.1007/bf03544472.
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AbstractBased on microsatellite prospection, we isolated and characterized 21 microsatellite markers for the Sooty Swift (Cypseloides fumigatus) and tested the cross-amplification in the White-collared Swift (Streptoprocne zonaris). Both species are New World species included in the Apodidae family. From these 21, only 13 loci were polymorphic in the Sooty Swift, and their levels of polymorphism were surprisingly low compared to related species. Cross-amplification in the White-collared Swift was successful for 11 loci of the 13 polymorphic found for the Sooty Swift, but seven were monomorphic and four were biallelic. The microsatellites described here could be useful in future genetic population studies for Sooty Swifts and related species.
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Vanpé, C., E. Buschiazzo, J. Abdelkrim, G. Morrow, S. C. Nicol y N. J. Gemmell. "Development of microsatellite markers for the short-beaked echidna using three different approaches". Australian Journal of Zoology 57, n.º 4 (2009): 219. http://dx.doi.org/10.1071/zo09033.
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We used three different methods, size-selected genomic library, cross-species amplification of a mammal-wide set of conserved microsatellites and genomic sequencing, to develop a panel of 43 microsatellite loci for the short-beaked echidna (Tachyglossus aculeatus). These loci were screened against 13 individuals from three different regions (Tasmania, Kangaroo Island, Perth region), spanning the breadth of the range of the short-beaked echidna. Nine of the 43 tested loci amplified reliably, generated clear peaks on the electropherogram and were polymorphic, with the number of alleles per locus ranging from two to eight (mean = 3.78) in the individuals tested. Polymorphic information content ranged from 0.16 to 0.78, and expected heterozygosity ranged from 0.19 to 0.84. One of the nine microsatellites showed a heterozygote deficit, suggesting a high probability of null alleles. The genomic sequencing approach using data derived from the Roche FLX platform is likely to provide the most promising method to develop echidna microsatellites. The microsatellite markers developed here will be useful tools to study population genetic structure, gene flow, kinship and parentage in Tachyglossus sp. and potentially also in endangered Zaglossus species.
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Purificacion, Marynold, Roslina Binti Mohd Shah, Thierry De Meeûs, Saripah Binti Bakar, Anisah Bintil Savantil, Meriam Mohd Yusof, Divina Amalin et al. "Development and characterization of microsatellite markers for population genetics of the cocoa pod borer Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillaridae)". PLOS ONE 19, n.º 4 (11 de abril de 2024): e0297662. http://dx.doi.org/10.1371/journal.pone.0297662.
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The cocoa pod borer (CPB) Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillaridae) is one of the major constraints for cocoa production in South East Asia. In addition to cultural and chemical control methods, autocidal control tactics such as the Sterile Insect Technique (SIT) could be an efficient addition to the currently control strategy, however SIT implementation will depend on the population genetics of the targeted pest. The aim of the present work was to search for suitable microsatellite loci in the genome of CPB that is partially sequenced. Twelve microsatellites were initially selected and used to analyze moths collected from Indonesia, Malaysia, and the Philippines. A quality control verification process was carried out and seven microsatellites found to be suitable and efficient to distinguish differences between CPB populations from different locations. The selected microsatellites were also tested against a closely related species, i.e. the lychee fruit borer Conopomorpha sinensis (LFB) from Vietnam and eight loci were found to be suitable. The availability of these novel microsatellite loci will provide useful tools for the analysis of the population genetics and gene flow of these pests, to select suitable CPB strains to implement the SIT.
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Zapata, Carlos, Santiago Rodríguez, Guillermo Visedo y Felipe Sacristán. "Spectrum of Nonrandom Associations Between Microsatellite Loci on Human Chromosome 11p15". Genetics 158, n.º 3 (1 de julio de 2001): 1235–51. http://dx.doi.org/10.1093/genetics/158.3.1235.
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Abstract Most evidence about nonrandom association of alleles at different loci, or gametic disequilibrium, across extensive anonymous regions of the human genome is based on the analysis of overall disequilibrium between pairs of microsatellites. However, analysis of interallelic associations is also necessary for a more complete description of disequilibrium. Here, we report a study characterizing the frequency and strength of both overall and interallelic disequilibrium between pairs of 12 microsatellite loci (CA repeats) spanning 19 cM (14 Mb) on human chromosome 11p15, in a large sample (810 haplotypes deduced from 405 individuals) drawn from a single population. Characterization of disequilibrium was carried out, taking into account the sign of the observed disequilibria. This strategy facilitates detection of associations and gives more accurate estimates of their intensities. Our results demonstrate that the incidence of disequilibrium over an extensive human chromosomal region is much greater than is commonly considered for populations that have expanded in size. In total, 44% of the pairs of microsatellite loci and 18% of the pairs of alleles showed significant nonrandom association. All the loci were involved in disequilibrium, although both the frequency and strength of interallelic disequilibrium were distributed nonuniformly along 11p15. These findings are especially relevant since significant associations were detected between loci separated by as much as 17–19 cM (7 cM on average). It was also found that the overall disequilibrium masks complicated patterns of association between pairs of alleles, dependent on their frequency and size. We suggest that the complex mutational dynamics at microsatellite loci could explain the allele-dependent disequilibrium patterns. These observations are also relevant to evaluation of the usefulness of microsatellite markers for fine-scale localization of disease genes.
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Dumas, Valérie, Stéphane Herder, Aïcha Bebba, Cécile Cadoux-Barnabé, Christian Bellec y Gérard Cuny. "Polymorphic microsatellites in Simulium damnosum s.l. and their use for differentiating two savannah populations: implications for epidemiological studies". Genome 41, n.º 2 (1 de abril de 1998): 154–61. http://dx.doi.org/10.1139/g97-113.
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In West Africa, Onchocerca volvulus, the cause of human onchocerciasis, is transmitted by sibling species of the Simulium damnosum complex. Little is known about blackfly intraspecific variability and its consequences on vectorial capacity. This study reports the use of microsatellite markers for differentiating populations of S. damnosum s.l. Five microsatellite loci were characterized and used to analyze individuals from two savannah populations in Mali, 120 km apart. Four loci were highly polymorphic, having 8-12 alleles per locus and gene diversities ranging from 77.9 to 88.2%. A significant heterozygote deficiency was observed in the two populations. This may arise from inbreeding, population structure (the Walhund effect), or the presence of null alleles. To test this last hypothesis, new primers were designed for two loci and used to analyze homozygous individuals. After correcting for null alleles, heterozygote deficit persisted. Population subdivision in the two foci remains the most likely explanation. Our results indicate that microsatellite markers could differentiate fly populations, making them valuable tools for the study of population genetic structure.Key words: Simulium damnosum s.l., microsatellites, polymorphism, population structure, population genetics, null alleles.
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Baghela, Abhishek, M. Thungapathra, M. R. Shivaprakash y Arunaloke Chakrabarti. "Multilocus microsatellite typing for Rhizopus oryzae". Journal of Medical Microbiology 59, n.º 12 (1 de diciembre de 2010): 1449–55. http://dx.doi.org/10.1099/jmm.0.023002-0.
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Rhizopus oryzae is the most frequent causative agent of zygomycosis. Although zygomycosis causes considerable morbidity and mortality in immunocompromised patients, the epidemiology of the disease is not well studied and no standard molecular typing method has been described for any of the causative agents. Here we describe a multilocus microsatellite typing (MLMT) method for R. oryzae. R. oryzae genome sequences were downloaded from the Fungal Genome Initiative database (Broad Institute). The intergenic regions and ORFs of approximately 5.7 Mb were screened for repeat regions with the help of the online repeat search tool Repeat Masker. Of the 30 microsatellite loci identified, 3 microsatellites [RO3, (CCT) n ; RO4, (TA) n ; and RO8, (GAA)(GGA) n ] were selected after validation of the ability to amplify them and their size variation in 8 randomly selected clinical isolates of R. oryzae. Nucleotide sequence analysis of these loci demonstrated polymorphism in the microsatellite repeat number. The capabilities of these microsatellite loci were assessed for strain differentiation on 30 clinical isolates, based on fragment size determination in an automated capillary electrophoresis using fluorescent labelled primers. These three polymorphic microsatellite loci were found to have good discriminatory power (D) (RO3, D=0.846; RO4, D=0.747; RO8, D=0.742; with a combined D=0.986) and stability for seven subcultures. It was also confirmed that the MLMT method may be applied to both R. oryzae and Rhizopus delemar (a proposed new species), although MLMT analysis could not differentiate them into two clusters. The MLMT system, described here for what is believed to be the first time for a zygomycotic fungus, holds promise as a powerful tool for the strain typing of R. oryzae.