Academic literature on the topic 'Heteromorphic autosomes'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Contents
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Heteromorphic autosomes.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Heteromorphic autosomes"
1
Kejnovský, Eduard, Jan Vrána, Sachihiro Matsunaga, Přemysl Souček, Jiří Široký, Jaroslav Doležel, and Boris Vyskot. "Localization of Male-Specifically Expressed MROS Genes of Silene latifolia by PCR on Flow-Sorted Sex Chromosomes and Autosomes." Genetics 158, no. 3 (July 1, 2001): 1269–77. http://dx.doi.org/10.1093/genetics/158.3.1269.
Full textAbstract:
Abstract The dioecious white campion Silene latifolia (syn. Melandrium album) has heteromorphic sex chromosomes, XX in females and XY in males, that are larger than the autosomes and enable their separation by flow sorting. The group of MROS genes, the first male-specifically expressed genes in dioecious plants, was recently identified in S. latifolia. To localize the MROS genes, we used the flow-sorted X chromosomes and autosomes as a template for PCR with internal primers. Our results indicate that the MROS3 gene is located in at least two copies tandemly arranged on the X chromosome with additional copy(ies) on the autosome(s), while MROS1, MROS2, and MROS4 are exclusively autosomal. The specificity of PCR products was checked by digestion with a restriction enzyme or reamplification using nested primers. Homology search of databases has shown the presence of five MROS3 homologues in A. thaliana, four of them arranged in two tandems, each consisting of two copies. We conclude that MROS3 is a low-copy gene family, connected with the proper pollen development, which is present not only in dioecious but also in other dicot plant species.
2
Mahesh, G., N. B. Ramachandra, and H. A. Ranganath. "Autoradiographic study of transcription and dosage compensation in the sex and neo-sex chromosome of Drosophila nasuta nasuta and Drosophila nasuta albomicans." Genome 44, no. 1 (February 1, 2001): 71–78. http://dx.doi.org/10.1139/g00-100.
Full textAbstract:
Cellular autoradiography is used to study the transcription patterns of the polytene X chromosomes in Drosophila nasuta nasuta and D. n. albomicans. D. n. nasuta, with 2n = 8, includes a pair of complete heteromorphic sex chromosomes, whereas D. n. albomicans, with 2n = 6, has a pair of metacentric neo-sex chromosomes representing incomplete heteromorphic sex chromosomes. The neo-X chromosome has two euchromatic arms, one representing the ancestral X while the other represents the ancestral autosome 3 chromosomes. The metacentric neo-Y chromosome has one arm with a complete heterochromatic ancestral Y and the other arm with a euchromatic ancestral autosome 3. The transcription study has revealed that the X chromosome in D. n. nasuta is hyperactive, suggesting complete dosage compensation, while in the neo-X chromosome of D. n. albomicans the ancestral X chromosome is hyperactive and the ancestral autosome 3, which is part of the neo-sex chromosome, is similar to any other autosomes. This finding shows dosage compensation on one arm (XLx/) of the neo-X chromosome, while the other arm (XR3/YR3) is not dosage compensated and has yet to acquire the dosage compensatory mechanism.Key words: Drosophila, chromosomal races, neo-sex chromosome, transcription and dosage compensation.
3
Tomkiel, John E., Barbara T. Wakimoto, and Albert Briscoe. "The teflon Gene Is Required for Maintenance of Autosomal Homolog Pairing at Meiosis I in Male Drosophila melanogaster." Genetics 157, no. 1 (January 1, 2001): 273–81. http://dx.doi.org/10.1093/genetics/157.1.273.
Full textAbstract:
Abstract In recombination-proficient organisms, chiasmata appear to mediate associations between homologs at metaphase of meiosis I. It is less clear how homolog associations are maintained in organisms that lack recombination, such as male Drosophila. In lieu of chiasmata and synaptonemal complexes, there must be molecules that balance poleward forces exerted across homologous centromeres. Here we describe the genetic and cytological characterization of four EMS-induced mutations in teflon (tef), a gene involved in this process in Drosophila melanogaster. All four alleles are male specific and cause meiosis I-specific nondisjunction of the autosomes. They do not measurably perturb sex chromosome segregation, suggesting that there are differences in the genetic control of autosome and sex chromosome segregation in males. Meiotic transmission of univalent chromosomes is unaffected in tef mutants, implicating the tef product in a pairing-dependent process. The segregation of translocations between sex chromosomes and autosomes is altered in tef mutants in a manner that supports this hypothesis. Consistent with these genetic observations, cytological examination of meiotic chromosomes suggests a role of tef in regulating or mediating pairing of autosomal bivalents at meiosis I. We discuss implications of this finding in regard to the evolution of heteromorphic sex chromosomes and the mechanisms that ensure chromosome disjunction in the absence of recombination.
4
Singchat, Worapong, Syed Farhan Ahmad, Nararat Laopichienpong, Aorarat Suntronpong, Thitipong Panthum, Darren K. Griffin, and Kornsorn Srikulnath. "Snake W Sex Chromosome: The Shadow of Ancestral Amniote Super-Sex Chromosome." Cells 9, no. 11 (October 31, 2020): 2386. http://dx.doi.org/10.3390/cells9112386.
Full textAbstract:
Heteromorphic sex chromosomes, particularly the ZZ/ZW sex chromosome system of birds and some reptiles, undergo evolutionary dynamics distinct from those of autosomes. The W sex chromosome is a unique karyological member of this heteromorphic pair, which has been extensively studied in snakes to explore the origin, evolution, and genetic diversity of amniote sex chromosomes. The snake W sex chromosome offers a fascinating model system to elucidate ancestral trajectories that have resulted in genetic divergence of amniote sex chromosomes. Although the principal mechanism driving evolution of the amniote sex chromosome remains obscure, an emerging hypothesis, supported by studies of W sex chromosomes of squamate reptiles and snakes, suggests that sex chromosomes share varied genomic blocks across several amniote lineages. This implies the possible split of an ancestral super-sex chromosome via chromosomal rearrangements. We review the major findings pertaining to sex chromosomal profiles in amniotes and discuss the evolution of an ancestral super-sex chromosome by collating recent evidence sourced mainly from the snake W sex chromosome analysis. We highlight the role of repeat-mediated sex chromosome conformation and present a genomic landscape of snake Z and W chromosomes, which reveals the relative abundance of major repeats, and identifies the expansion of certain transposable elements. The latest revolution in chromosomics, i.e., complete telomere-to-telomere assembly, offers mechanistic insights into the evolutionary origin of sex chromosomes.
5
Rovatsos, Michail, Martina Johnson Pokorná, and Lukáš Kratochvíl. "Differentiation of Sex Chromosomes and Karyotype Characterisation in the Dragonsnake Xenodermus javanicus (Squamata: Xenodermatidae)." Cytogenetic and Genome Research 147, no. 1 (2015): 48–54. http://dx.doi.org/10.1159/000441646.
Full textAbstract:
Highly differentiated heteromorphic ZZ/ZW sex chromosomes with a heterochromatic W are a basic principle among advanced snakes of the lineage Colubroidea, while other snake lineages generally lack these characteristics. For the first time, we cytogenetically examined the dragonsnake, Xenodermus javanicus, a member of the family Xenodermatidae, which is phylogenetically nested between snake lineages with and without differentiated sex chromosomes. Although most snakes have a karyotype with a stable chromosomal number of 2n = 36, the dragonsnake has an unusual, derived karyotype with 2n = 32 chromosomes. We found that heteromorphic ZZ/ZW sex chromosomes with a heterochromatic W are present in the dragonsnake, which suggests that the emergence of a highly differentiated W sex chromosome within snakes predates the split of Xenodermatidae and the clade including families Pareatidae, Viperidae, Homalopsidae, Lamprophiidae, Elapidae, and Colubridae. Although accumulations of interstitial telomeric sequences have not been previously reported in snakes, by using FISH with a telomeric probe we discovered them in 6 pairs of autosomes as well as in the W sex chromosome of the dragonsnake. Similarly to advanced snakes, the sex chromosomes of the dragonsnake have a significant accumulation of repeats containing a (GATA)n sequence. The results facilitate the dating of the differentiation of sex chromosomes within snakes back to the split between Xenodermatidae and other advanced snakes, i.e. around 40-75 mya.
6
McAllister, Bryant F. "Sequence Differentiation Associated With an Inversion on the Neo-X Chromosome of Drosophila americana." Genetics 165, no. 3 (November 1, 2003): 1317–28. http://dx.doi.org/10.1093/genetics/165.3.1317.
Full textAbstract:
Abstract Sex chromosomes originate from pairs of autosomes that acquire controlling genes in the sex-determining cascade. Universal mechanisms apparently influence the evolution of sex chromosomes, because this chromosomal pair is characteristically heteromorphic in a broad range of organisms. To examine the pattern of initial differentiation between sex chromosomes, sequence analyses were performed on a pair of newly formed sex chromosomes in Drosophila americana. This species has neo-sex chromosomes as a result of a centromeric fusion between the X chromosome and an autosome. Sequences were analyzed from the Alcohol dehydrogenase (Adh), big brain (bib), and timeless (tim) gene regions, which represent separate positions along this pair of neo-sex chromosomes. In the northwestern range of the species, the bib and Adh regions exhibit significant sequence differentiation for neo-X chromosomes relative to neo-Y chromosomes from the same geographic region and other chromosomal populations of D. americana. Furthermore, a nucleotide site defining a common haplotype in bib is shown to be associated with a paracentric inversion [In(4)ab] on the neo-X chromosome, and this inversion suppresses recombination between neo-X and neo-Y chromosomes. These observations are consistent with the inversion acting as a recombination modifier that suppresses exchange between these neo-sex chromosomes, as predicted by models of sex chromosome evolution.
7
Pucci, Marcela B., Patricia Barbosa, Viviane Nogaroto, Mara C. Almeida, Roberto F. Artoni, Priscila C. Scacchetti, José C. Pansonato-Alves, Fausto Foresti, Orlando Moreira-Filho, and Marcelo R. Vicari. "Chromosomal Spreading of Microsatellites and (TTAGGG)n Sequences in the Characidium zebra and C. gomesi Genomes (Characiformes: Crenuchidae)." Cytogenetic and Genome Research 149, no. 3 (2016): 182–90. http://dx.doi.org/10.1159/000447959.
Full textAbstract:
Sex chromosome evolution involves the accumulation of repeat sequences such as multigenic families, noncoding repetitive DNA (satellite, minisatellite, and microsatellite), and mobile elements such as transposons and retrotransposons. Most species of Characidium exhibit heteromorphic ZZ/ZW sex chromosomes; the W is characterized by an intense accumulation of repetitive DNA including dispersed satellite DNA sequences and transposable elements. The aim of this study was to analyze the distribution pattern of 18 different tandem repeats, including (GATA)n and (TTAGGG)n, in the genomes of C. zebra and C. gomesi, especially in the C. gomesi W chromosome. In the C. gomesi W chromosome, weak signals were seen for (CAA)10, (CAC)10, (CAT)10, (CGG)10, (GAC)10, and (CA)15 probes. (GA)15 and (TA)15 hybridized to the autosomes but not to the W chromosome. The (GATA)n probe hybridized to the short arms of the W chromosome as well as the (CG)15 probe. The (GATA)n repeat is known to be a protein-binding motif. GATA-binding proteins are necessary for the decondensation of heterochromatic regions that hold coding genes, especially in some heteromorphic sex chromosomes that may keep genes related to oocyte development. The (TAA)10 repeat is accumulated in the entire W chromosome, and this microsatellite accumulation is probably involved in the sex chromosome differentiation process and crossover suppression in C. gomesi. These additional data on the W chromosome DNA composition help to explain the evolution of sex chromosomes in Characidium.
8
Kounatidis, Ilias, Nikolaos Papadopoulos, Kostas Bourtzis, and Penelope Mavragani-Tsipidou. "Genetic and cytogenetic analysis of the fruit fly Rhagoletis cerasi (Diptera: Tephritidae)." Genome 51, no. 7 (July 2008): 479–91. http://dx.doi.org/10.1139/g08-032.
Full textAbstract:
The European cherry fruit fly, Rhagoletis cerasi , is a major agricultural pest for which biological, genetic, and cytogenetic information is limited. We report here a cytogenetic analysis of 4 natural Greek populations of R. cerasi, all of them infected with the endosymbiotic bacterium Wolbachia pipientis . The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of 6 pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement has shown a total of 5 long chromosomes (10 polytene arms) that correspond to the 5 autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The most prominent landmarks of each polytene chromosome, the “weak points”, and the unusual asynapsis of homologous pairs of polytene chromosomes at certain regions of the polytene elements are also presented and discussed.
9
Bačovský, Václav, Tomáš Janíček, and Roman Hobza. "The Sister Chromatid Division of the Heteromorphic Sex Chromosomes in Silene Species and Their Transmissibility towards the Mitosis." International Journal of Molecular Sciences 23, no. 5 (February 22, 2022): 2422. http://dx.doi.org/10.3390/ijms23052422.
Full textAbstract:
Young sex chromosomes possess unique and ongoing dynamics that allow us to understand processes that have an impact on their evolution and divergence. The genus Silene includes species with evolutionarily young sex chromosomes, and two species of section Melandrium, namely Silene latifolia (24, XY) and Silene dioica (24, XY), are well-established models of sex chromosome evolution, Y chromosome degeneration, and sex determination. In both species, the X and Y chromosomes are strongly heteromorphic and differ in the genomic composition compared to the autosomes. It is generally accepted that for proper cell division, the longest chromosomal arm must not exceed half of the average length of the spindle axis at telophase. Yet, it is not clear what are the dynamics between males and females during mitosis and how the cell compensates for the presence of the large Y chromosome in one sex. Using hydroxyurea cell synchronization and 2D/3D microscopy, we determined the position of the sex chromosomes during the mitotic cell cycle and determined the upper limit for the expansion of sex chromosome non-recombining region. Using 3D specimen preparations, we found that the velocity of the large chromosomes is compensated by the distant positioning from the central interpolar axis, confirming previous mathematical modulations.
10
Romanenko, Svetlana A., Vladimir G. Malikov, Ahmad Mahmoudi, Feodor N. Golenishchev, Natalya A. Lemskaya, Jorge C. Pereira, Vladimir A. Trifonov, et al. "New Data on Comparative Cytogenetics of the Mouse-Like Hamsters (Calomyscus Thomas, 1905) from Iran and Turkmenistan." Genes 12, no. 7 (June 24, 2021): 964. http://dx.doi.org/10.3390/genes12070964.
Full textAbstract:
The taxonomy of the genus Calomyscus remains controversial. According to the latest systematics the genus includes eight species with great karyotypic variation. Here, we studied karyotypes of 14 Calomyscus individuals from different regions of Iran and Turkmenistan using a new set of chromosome painting probes from a Calomyscus sp. male (2n = 46, XY; Shahr-e-Kord-Soreshjan-Cheshme Maiak Province). We showed the retention of large syntenic blocks in karyotypes of individuals with identical chromosome numbers. The only rearrangement (fusion 2/21) differentiated Calomyscus elburzensis, Calomyscus mystax mystax, and Calomyscus sp. from Isfahan Province with 2n = 44 from karyotypes of C. bailwardi, Calomyscus sp. from Shahr-e-Kord, Chahar Mahal and Bakhtiari-Aloni, and Khuzestan-Izeh Provinces with 2n = 46. The individuals from Shahdad tunnel, Kerman Province with 2n = 51–52 demonstrated non-centric fissions of chromosomes 4, 5, and 6 of the 46-chromosomal form with the formation of separate small acrocentrics. A heteromorphic pair of chromosomes in a specimen with 2n = 51 resulted from a fusion of two autosomes. C-banding and chromomycin A3-DAPI staining after G-banding showed extensive heterochromatin variation between individuals.
Dissertations / Theses on the topic "Heteromorphic autosomes"
1
Toledo-Flores, Deborah Fernanda. "Evolution of mammalian sex chromosomes and sex determination genes: insights from monotremes." Thesis, 2015. http://hdl.handle.net/2440/97382.
Full textAbstract:
Genetic sex determination systems are generally based on the presence of differentiated sex chromosomes. Birds have a ZZ/ZW sex chromosome system in which males are ZZ and females ZW, whereas mammals have an XX/XY system with males being XY and females XX. Monotremes have an extraordinary sex chromosome system that consists of multiple sex chromosomes: 5X5Y in platypus and 5X4Y in echidna. Intriguingly, the monotreme sex chromosomes show extensive homology to the bird ZW and not to the therian XY. However, sex determination in monotremes is still a mystery; the Y-specific Sry gene that triggers male sex determination in therian mammals is absent and so far very few genes have been identified on Y chromosomes in monotremes. To gain more insights into the gene content of Y-chromosomes and to identify potential sex determination genes in the platypus a collaborative large scale transcriptomic approach led to the identification of new male specific genes including the anti-Muellerian hormone AMH that I mapped to Y₅, this makes Amhy an exciting new candidate for sex determination in monotremes. Platypus chromosome 6 is largely homologous to the therian X and therefore it represents the therian proto sex chromosome. In addition, this autosome features a large heteromorphic nucleolus organizer region (NOR) and associates with the sex chromosomes during male meiosis (Casey and Daish personal communication). I investigated chromosome 6 heteromorphism in both sexes and found a number of sex-specific characteristics related to the extent of the NOR heteromorphism, DNA methylation, silver staining patterns and interestingly, meiotic segregation bias. This raises the possibility that chromosome 6 may have commenced differentiation prior to monotreme therian divergence. These results led me to investigate the chromosome 6 borne gene Sox3, from which Sry evolved in therian mammals. This revealed a platypus male-specific Sox3 allele, which differs from the alleles observed also in females on the length of one of the Sox3
polyalanine tracts. This raises the possibility that Sox3 may be working differently in males and females. We have used our unique knowledge of monotreme sex chromosomes to determine the sex of captively bred echidnas. I used a PCR based genetic sexing technique that utilizes DNA from small hair samples and primers that amplify male-specific genes. Interestingly, I found that seven out of eight echidnas born in captivity were females. Furthermore, I found a Sox3 deletion in the only male echidna born in captivity. This gives us the unique opportunity to investigate the sexual development of an animal in which this gene is naturally deleted providing an exceptional situation in which to study monotreme sex determination. Furthermore, this sexing technique has the potential of being applied in the wild to investigate sex ratio in natural populations of monotremes, including the critically endangered long-beaked echidna.Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2015