Journal articles: 'Molecular genetics – Technique'

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Roberts, Robert. "Impact for molecular biology in cardiology." American Journal of Physiology-Lung Cellular and Molecular Physiology 261, no. 4 (October 1, 1991): L8—L14. http://dx.doi.org/10.1152/ajplung.1991.261.4.l8.

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The recent development and application of the techniques of recombinant DNA and molecular biology ignited an explosion in biomedical research, which has been embraced by medicine. However, cardiology as a subspecialty has been slower in adopting these techniques, in part because the heart is a nonproliferating organ and in part because it was not easily accessible until recently. The techniques of recombinant DNA were not possible until the 1970s. In that decade four major discoveries occurred that launched molecular biology into the 21st century. These seminal contributions were 1) the discovery and application of specific restriction endonucleases, 2) the discovery of reverse transcriptase, 3) the development of the cloning technique, and 4) the ability to rapidly sequence nucleic acids. The techniques of recombinant DNA offer several unique advantages over existing scientific disciplines, such as the abilities: 1) to perform in vivo structure-function analysis, 2) to genetically engineer drugs, 3) to perform diagnostic in situ hybridization, 4) to isolate genes responsible for hereditary disorders, and 5) to understand the genetic regulation of cardiac growth. These techniques are discussed in their application to cardiac disorders, including the development of new recombinant molecules for the treatment of coronary thrombosis and the potential to modulate the cardiac growth response to various forms of injury such as myocardial infarction and hypertension. cardiac growth; genetic engineering; molecular genetics; structure function analysis

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Roberts, Robert. "Impact for molecular biology in cardiology." American Journal of Physiology-Heart and Circulatory Physiology 261, no. 4 (October 1, 1991): 8–14. http://dx.doi.org/10.1152/ajpheart.1991.261.4.8.

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The recent development and application of the techniques of recombinant DNA and molecular biology ignited an explosion in biomedical research, which has been embraced by medicine. However, cardiology as a subspecialty has been slower in adopting these techniques, in part because the heart is a nonproliferating organ and in part because it was not easily accessible until recently. The techniques of recombinant DNA were not possible until the 1970s. In that decade four major discoveries occurred that launched molecular biology into the 21st century. These seminal contributions were 1) the discovery and application of specific restriction endonucleases, 2) the discovery of reverse transcriptase, 3) the development of the cloning technique, and 4) the ability to rapidly sequence nucleic acids. The techniques of recombinant DNA offer several unique advantages over existing scientific disciplines, such as the abilities: 1) to perform in vivo structure-function analysis, 2) to genetically engineer drugs, 3) to perform diagnostic in situ hybridization, 4) to isolate genes responsible for hereditary disorders, and 5) to understand the genetic regulation of cardiac growth. These techniques are discussed in their application to cardiac disorders, including the development of new recombinant molecules for the treatment of coronary thrombosis and the potential to modulate the cardiac growth response to various forms of injury such as myocardial infarction and hypertension. cardiac growth; genetic engineering; molecular genetics; structure function analysis

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Lynch, M., and P. E. Jarrell. "A method for calibrating molecular clocks and its application to animal mitochondrial DNA." Genetics 135, no. 4 (December 1, 1993): 1197–208. http://dx.doi.org/10.1093/genetics/135.4.1197.

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Abstract A generalized least-squares procedure is introduced for the calibration of molecular clocks and applied to the complete mitochondrial DNA sequences of 13 animal species. The proposed technique accounts for both nonindependence and heteroscedasticity of molecular-distance data, problems that have not been taken into to account in such analyses in the past. When sequence-identity data are transformed to account for multiple substitutions/site, the molecular divergence scales linearly with time, but with substantially more variation in the substitution rate than expected under a Poisson model. Significant levels of divergence are predicted at zero divergence time for most loci, suggesting high levels of site-specific heterozygosity among mtDNA molecules establishing in sister taxa. For nearly all loci, the baseline heterozygosity is lower and the substitution rate is higher in mammals relative to other animals. There is considerable variation in the evolutionary rate among loci but no compelling evidence that the average rate of mtDNA evolution is elevated with respect to that of nuclear DNA. Using the observed patterns of interspecific divergence, empirical estimates are derived for the mean coalescence times of organelles colonizing sister taxa.

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STEFANINI, FEDERICO MATTIA, and ALESSANDRO CAMUSSI. "Information in molecular profile components evaluated by a Genetic Classifier System: a case study in Picea abies Karst." Genetical Research 70, no. 3 (December 1997): 205–13. http://dx.doi.org/10.1017/s001667239700298x.

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Individual records from the coding of molecular polymorphism (molecular profiles) are particularly useful for the identification of clones or cultivars, in pedigree analysis, in the estimation of genetic distances and relatedness, and as a tool in genome mapping and population genetics. A parametric statistical analysis of molecular profile components can be infeasible because of the huge number of observed markers, the presence of missing values and the high number of parameters required to evaluate the importance of interactions among markers. Moreover, new powerful molecular techniques make possible the analysis of numerous markers at one time; therefore parametric statistical methods could result in troublesome models with more parameters than data. The field of computer-based techniques offers new strategies to cope with the complexity of molecular profiles. We suggest the use of a Genetic Classifier System to evaluate the importance of profile components. The procedure is based on a Genetic Algorithm approach, a numerical technique that simulates some features of the natural selection process to solve problems. A set of isozyme data from a Norway spruce population is analysed in order to assess their ability to predict the individual plant response to the presence of abiotic stresses. The results, obtained by three different computer simulations, show that this computer-based approach is particularly effective for ranking profile components according to their relevance. Genetic Classifier Systems could also be used as a preliminary step to reduce the complexity of molecular data sets.

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Gavrilov, Alexey A., Helena V. Chetverina, Elina S. Chermnykh, Sergey V. Razin, and Alexander B. Chetverin. "Quantitative analysis of genomic element interactions by molecular colony technique." Nucleic Acids Research 42, no. 5 (December 24, 2013): e36-e36. http://dx.doi.org/10.1093/nar/gkt1322.

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Abstract Distant genomic elements were found to interact within the folded eukaryotic genome. However, the used experimental approach (chromosome conformation capture, 3C) enables neither determination of the percentage of cells in which the interactions occur nor demonstration of simultaneous interaction of >2 genomic elements. Each of the above can be done using in-gel replication of interacting DNA segments, the technique reported here. Chromatin fragments released from formaldehyde–cross-linked cells by sodium dodecyl sulfate extraction and sonication are distributed in a polyacrylamide gel layer followed by amplification of selected test regions directly in the gel by multiplex polymerase chain reaction. The fragments that have been cross-linked and separate fragments give rise to multi- and monocomponent molecular colonies, respectively, which can be distinguished and counted. Using in-gel replication of interacting DNA segments, we demonstrate that in the material from mouse erythroid cells, the majority of fragments containing the promoters of active β-globin genes and their remote enhancers do not form complexes stable enough to survive sodium dodecyl sulfate extraction and sonication. This indicates that either these elements do not interact directly in the majority of cells at a given time moment, or the formed DNA–protein complex cannot be stabilized by formaldehyde cross-linking.

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Ogata, Hiroyuki, Yutaka Akiyama, and Minoru Kanehisa. "A genetic algorithm based molecular modeling technique for RNA stem-loop structures." Nucleic Acids Research 23, no. 3 (1995): 419–26. http://dx.doi.org/10.1093/nar/23.3.419.

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Schön, Isa, and Koen Martens. "Phylogenetic Reconstructions of Ostracodes – A Molecular Approach." Paleontological Society Papers 9 (November 2003): 71–88. http://dx.doi.org/10.1017/s1089332600002151.

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Molecular work on ostracodes has thus far either used allozyme-based or DNA-based techniques. The application of allozyme-based methods has provided numerous data on population genetics and reproductive modes in ostracodes. With this technique, it has also been possible to construct phylogenies, although these have been restricted to distance-based methods. With the usage of DNA-based methods, a new era in ostracode research has begun. It is now possible to obtain accurate estimates for genetic diversities at very fine scales, even within individuals. The DNA-based approach is also very useful for reconstructing evolutionary histories at different taxonomic levels. Within species, for example, phylogenies reveal past episodes of dispersal and genetic exchange. Together with morphological data, DNA sequence data can test for congruence of molecular and morphological evolution and variability. At high taxonomic levels, DNA sequence data provide information on mechanisms of evolution and speciation. This allows for testing whether a certain, morphological feature has evolved once or several times independently. By applying the principle of the molecular clock, DNA sequence data provide relative age estimates that can be calibrated against fossil data and be linked to past climatic or geological events.

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Fukatsu, Takema. "Acetone preservation: a practical technique for molecular analysis." Molecular Ecology 8, no. 11 (November 1999): 1935–45. http://dx.doi.org/10.1046/j.1365-294x.1999.00795.x.

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Bale, Sherri J. "When Genetics Gets under Your Skin." Journal of Cutaneous Medicine and Surgery 1, no. 2 (October 1996): 97–100. http://dx.doi.org/10.1177/120347549600100208.

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Background: Only recently has the advent of the use of modern statistical and molecular genetic techniques begun to increase our understanding of the study of dermatology and skin biology. Objective: This paper will briefly outline several statistical techniques that are used in genetic studies of skin disease by reviewing these techniques, the types of questions that can be answered using them, and issues that should be considered in evaluating and interpreting papers that use them. Methods: A discussion of association studies, segregation analyses, and linkage analyses with respect to skin diseases is presented. Results: Association studies can be used to identify both genetic and environmental risk factors for disease. Segregation analyses are used to identify the underlying mechanism for disease aggregation in families. Linkage analysis is used to map disease genes to chromosomes. Conclusion: Dermatologists should be familiar with the types of genetic questions that can be answered with each technique, and should remain aware of the limitations in interpretation.

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Gui, Yijie, Guanghao Yan, Shiping Bo, Zhijun Tong, Yu Wang, Bingguang Xiao, Xiuping Lu, Yongping Li, Weiren Wu, and Longjiang Fan. "iSNAP: a small RNA-based molecular marker technique." Plant Breeding 130, no. 5 (June 2, 2011): 515–20. http://dx.doi.org/10.1111/j.1439-0523.2011.01872.x.

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Szabo, Eva, and Gail L. Shaw. "Intermediate Markers and Molecular Genetics of Lung Carcinogenesis." Cancer Control 4, no. 2 (March 1997): 109–17. http://dx.doi.org/10.1177/107327489700400201.

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Background Various options are available for the local control of cancer in the breast - mastectomy, conservation therapy, and mastectomy with reconstruction. Methods To evaluate the benefits and drawbacks of the available management options, the authors combine their extensive experience with a review of the literature on outcomes from these approaches. Results Conservation therapy provides survival outcomes similar to those from mastectomy. Differences in local recurrence rates can be minimized by close adherence to guidelines for patient selection, operative approach, and radiation technique. Conclusions The role of the physician in selecting a local therapy for breast cancer has changed from one of informing the patient of the treatment to assessing the presence of medical contraindications to any of the treatments, educating the patients on each treatment approach, providing access to multidisciplinary consultation, and allowing the patient to choose an appropriate treatment approach.

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Hart, T. C., M. L. Marazita, and J. T. Wright. "The Impact of Molecular Genetics on Oral Health Paradigms." Critical Reviews in Oral Biology & Medicine 11, no. 1 (January 2000): 26–56. http://dx.doi.org/10.1177/10454411000110010201.

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As a result of our increased understanding of the human genome, and the functional interrelationships of gene products with each other and with the environment, it is becoming increasingly evident that many human diseases are influenced by heritable alterations in the structure or function of genes. Significant advances in research methods and newly emerging partnerships between private and public sector interests are creating new possibilities for utilization of genetic information for the diagnosis and treatment of human diseases. The availability and application of genetic information to the understanding of normal and abnormal human growth and development are fundamentally changing the way we approach the study of human diseases. As a result, the issues and principles of medical genetics are coming to bear across all disciplines of health care. In this review, we discuss some of the potential applications of human molecular genetics for the diagnosis and treatment of oral diseases. This discussion is presented in the context of the ongoing technological advances and conceptual changes that are occurring in the field of medical genetics. To realize the promise of this new molecular genetics, we must be prepared to foresee the possibilities and to incorporate these newly emergent technologies into the evolving discipline of dentistry. By using examples of human conditions, we illustrate the broad application of this emerging technology to the study of simple as well as complex genetic diseases. Throughout this paper, we will use the following terminology: P enetrance—I n a population, defined as the proportion of individuals posessing a disease-causing genotype who express the disease phenotype. When this proportion is less than 100%, the disease is said to have reduced or incomplete penetrance. Polymerase chain reaction (PCR)-A technique for amplifying a large number of copies of a specific DNA sequence flanked by two oligonucleotide primers. The DNA is alternately heated and cooled in the presence of DNA polymerase and free nucleotides, so that the specified DNA segment is denatured, hybridized with primers, and extended by DNA polymerase. MIM-Mendelian Inheritance in Man catalogue number from V. McKusick's Mendelian Inheritance in man (OMIM, 1998).

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Infante-Malachias, Maria Elena, Karla Suemy Clemente Yotoko, and Ana Maria Lima de Azeredo Espin. "Random amplified polymorphic DNA of screwworm fly populations (Diptera: Calliphoridae) from Southeastern Brazil and Northern Argentina." Genome 42, no. 4 (August 1, 1999): 772–79. http://dx.doi.org/10.1139/g98-164.

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The screwworm fly Cochliomyia hominivorax is one of the most important agents of traumatic myiasis throughout neotropical regions. In this work, we optimized the technique of RAPD-PCR for these species and used it to study the genetic variability among seven populations (six from southeastern Brazil and one from northern Argentina) of C. hominivorax. RAPD fingerprints showed high variation for 12 primers used, revealing 209 presumptive loci of which 198 were polymorphic. Marker pattern relationships for these different populations were used to determine genetic relatedness, as well as to examine potential patterns of gene flow. Our interpretation of Lynch and Milligan's analogue of Wright's F(ST) was that C. hominivorax populations are genetically subdivided (F'(ST) for pooled samples = 0.122). Our data suggested that the subdivision detected in C. hominivorax populations by RAPD can be explained by the interplay of random factors affecting allele frequency changes. These results indicate that the RAPD-PCR technique is useful for revealing genetic variation in screwworm fly populations not detected by others techniques and can represent an efficient method for understanding the genetic structure and population genetic phenomena of this important pest.Key words: Cochliomyia hominivorax, screwworm fly, population genetics, gene flow.

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Lodolo, Elizabeth J., Willem H. Van Zyl, and Chris J. Rabie. "A rapid molecular technique to distinguish Fusarium species." Mycological Research 97, no. 3 (March 1993): 345–46. http://dx.doi.org/10.1016/s0953-7562(09)81133-7.

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Chen, Zhi-Yi, Yi-Xiang Wang, Feng Yang, Yan Lin, Qiu-Lan Zhou, and Yang-Ying Liao. "New Researches and Application Progress of Commonly Used Optical Molecular Imaging Technology." BioMed Research International 2014 (2014): 1–22. http://dx.doi.org/10.1155/2014/429198.

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Optical molecular imaging, a new medical imaging technique, is developed based on genomics, proteomics and modern optical imaging technique, characterized by non-invasiveness, non-radiativity, high cost-effectiveness, high resolution, high sensitivity and simple operation in comparison with conventional imaging modalities. Currently, it has become one of the most widely used molecular imaging techniques and has been applied in gene expression regulation and activity detection, biological development and cytological detection, drug research and development, pathogenesis research, pharmaceutical effect evaluation and therapeutic effect evaluation, and so forth, This paper will review the latest researches and application progresses of commonly used optical molecular imaging techniques such as bioluminescence imaging and fluorescence molecular imaging.

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Wijerathna, Yapa M. A. M. "Advances of Basic Molecular Biology Techniques: Potential to Apply in Plant Viroid Detection in Sri Lanka." International Journal of Phytopathology 1, no. 1 (December 15, 2012): 88–93. http://dx.doi.org/10.33687/phytopath.001.01.0020.

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Viroids are the smallest pathogens of plants. They are the cause of serious diseases on economic plants worldwide. Prevention and detection of the pathogens are the best method to reduce the economic loss from viroid infection. During last decade, genetics and molecular biology techniques have gained an increasing presence in plant pathology research. The purpose of this review is to highlight the most upgrade molecular biology techniques that have been used and studied recently. Most relevant published reports and hand skilled techniques have presented here with emphasis on suitable Viroid detection technique should be used for Sri Lanka.

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Pratim Mondal, Partha. "Probabilistic Optically-Selective Single-molecule Imaging Based Localization Encoded (POSSIBLE) microscopy for ultra-superresolution imaging." PLOS ONE 15, no. 11 (November 16, 2020): e0242452. http://dx.doi.org/10.1371/journal.pone.0242452.

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To be able to resolve molecular-clusters it is crucial to access vital information (such as, molecule density, cluster-size, and others) that are key in understanding disease progression and the underlying mechanism. Traditional single-molecule localization microscopy (SMLM) techniques use molecules of variable sizes (as determined by its localization precision (LP)) to reconstruct a super-resolution map. This results in an image with overlapping and superimposing PSFs (due to a wide size-spectrum of single-molecules) that undermine image resolution. Ideally, it should be possible to identify the brightest molecules (also termed as the fortunate molecules) to reconstruct ultra-superresolution map, provided sufficient statistics is available from the recorded data. Probabilistic Optically-Selective Single-molecule Imaging Based Localization Encoded (POSSIBLE) microscopy explores this possibility by introducing a narrow probability size-distribution of single-molecules (narrow size-spectrum about a predefined mean-size). The reconstruction begins by presetting the mean and variance of the narrow distribution function (Gaussian function). Subsequently, the dataset is processed and single-molecules are filtered by the Gaussian function to remove unfortunate molecules. The fortunate molecules thus retained are then mapped to reconstruct an ultra-superresolution map. In-principle, the POSSIBLE microscopy technique is capable of infinite resolution (resolution of the order of actual single-molecule size) provided enough fortunate molecules are experimentally detected. In short, bright molecules (with large emissivity) holds the key. Here, we demonstrate the POSSIBLE microscopy technique and reconstruct single-molecule images with an average PSF sizes of σ ± Δσ = 15 ± 10 nm, 30 ± 2 nm & 50 ± 2 nm. Results show better-resolved Dendra2-HA clusters with large cluster-density in transfected NIH3T3 fibroblast cells as compared to the traditional SMLM techniques. Cluster analysis indicates densely-packed HA molecules, HA-HA interaction, and a surge in the number of HA molecules per cluster post 24 Hrs of transfection. The study using POSSIBLE microscopy introduces new insights in influenza biology. We anticipate exciting applications in the multidisciplinary field of disease biology, oncology, and biomedical imaging.

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Mladenovic-Drinic, Snezana, Dragana Ignjatovic-Micic, Iva Eric, Violeta Andjelkovic, Drazen Jelovac, and Kosana Konstantinov. "Biotechnology in maize breeding." Genetika 36, no. 2 (2004): 93–109. http://dx.doi.org/10.2298/gensr0402093m.

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Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

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Andrade, Alexandre de, Paula Rezende Teixeira, Fábio Siviero, and Roberto Vicente Santelli. "A shortcut in phage screening technique." Genetics and Molecular Biology 28, no. 1 (March 2005): 150–51. http://dx.doi.org/10.1590/s1415-47572005000100025.

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Cui, Yingjie. "Confocal Imaging: Blood and Lymphatic Capillaries." Scientific World JOURNAL 6 (2006): 12–15. http://dx.doi.org/10.1100/tsw.2006.12.

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Traditional imaging techniques are quite limited for the study of the relationship between blood vessels and lymphatic vessels. Therefore, a new imaging technique is required based on blood vessel and lymphatic endothelial-specific molecular markers. In this short report, vascular molecular markers are reviewed and a new molecular imaging technique for blood vessel and lymphatic co-staining is introduced.

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Ma, Zhong, Cynthia Cooper, Hyun-Joo Kim, and Diane Janick-Buckner. "A Study of Rubisco through Western Blotting and Tissue Printing Techniques." CBE—Life Sciences Education 8, no. 2 (June 2009): 140–46. http://dx.doi.org/10.1187/cbe.09-01-0003.

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We describe a laboratory exercise developed for a cell biology course for second-year undergraduate biology majors. It was designed to introduce undergraduates to the basic molecular biology techniques of Western blotting and immunodetection coupled with the technique of tissue printing in detecting the presence, relative abundance, and distribution of ribulose-1,5-bisphosphate carboxylase in various plant materials. Pre- and postlab surveys indicated significant postlab gains in student understanding of all three lab techniques and relevant lecture topics. Additional postlab survey questions on student perception of the lab modules suggested that the laboratory exercises successfully met a series of pedagogical goals set by the instructors. The combination of these techniques provided a basis for quantitative and qualitative (visual) analysis of a biologically important enzyme and can be applied or modified readily to study other proteins and biological molecules in lab exercises for an introductory cell biology course or molecular biology course.

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Pérez-Enciso, Miguel, Miguel A. Toro, Michel Tenenhaus, and Daniel Gianola. "Combining Gene Expression and Molecular Marker Information for Mapping Complex Trait Genes: A Simulation Study." Genetics 164, no. 4 (August 1, 2003): 1597–606. http://dx.doi.org/10.1093/genetics/164.4.1597.

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Abstract A method for mapping complex trait genes using cDNA microarray and molecular marker data jointly is presented and illustrated via simulation. We introduce a novel approach for simulating phenotypes and genotypes conditionally on real, publicly available, microarray data. The model assumes an underlying continuous latent variable (liability) related to some measured cDNA expression levels. Partial least-squares logistic regression is used to estimate the liability under several scenarios where the level of gene interaction, the gene effect, and the number of cDNA levels affecting liability are varied. The results suggest that: (1) the usefulness of microarray data for gene mapping increases when both the number of cDNA levels in the underlying liability and the QTL effect decrease and when genes are coexpressed; (2) the correlation between estimated and true liability is large, at least under our simulation settings; (3) it is unlikely that cDNA clones identified as significant with partial least squares (or with some other technique) are the true responsible cDNAs, especially as the number of clones in the liability increases; (4) the number of putatively significant cDNA levels increases critically if cDNAs are coexpressed in a cluster (however, the proportion of true causal cDNAs within the significant ones is similar to that in a no-coexpression scenario); and (5) data reduction is needed to smooth out the variability encountered in expression levels when these are analyzed individually.

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Villar, M., F. Lefèvre, H. D. Bradshaw, and E. Teissier du Cros. "Molecular Genetics of Rust Resistance in Poplars (Melampsora larici-populina Kleb/Populus sp.) by Bulked Segregant Analysis in a 2 × 2 Factorial Mating Design." Genetics 143, no. 1 (May 1, 1996): 531–36. http://dx.doi.org/10.1093/genetics/143.1.531.

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Abstract With random amplified polymorphic DNA (RAPD) markers, we have tagged a genomic region in Populus sp. involved in qualitative resistance to Melumpsora larici-populina. Our approach was based on three steps: use of RAPD markers that can be quickly and efficiently researched; application of “bulked segregant analysis” technique on individuals of one interspecific family P. trichocarpa × P. deltoides to search for RAPD markers linked to resistance; and validation of these markers in two other families linked with the first one in a 2 × 2 factorial mating design. Of five detected markers, only one marker M03/04_480 was polymorphic in the three segregating families, involving 89 individuals and four different parents. We have estimated the recombination value of 1 cM with 1 cM sampling error.

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Kelley, Mark R., Inka P. Mims, Chris M. Farnet, Sherry A. Dicharry, and William R. Lee. "MOLECULAR ANALYSIS OF X-RAY-INDUCED ALCOHOL DEHYDROGENASE (Adh) NULL MUTATIONS IN DROSOPHILA MELANOGASTER." Genetics 109, no. 2 (February 1, 1985): 365–77. http://dx.doi.org/10.1093/genetics/109.2.365.

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ABSTRACT We have attempted to analyze at the molecular level mutants previously determined as having intragenic lesions caused by X-ray mutagenesis. C. S. Aaron isolated 33 null mutations at the Adh locus and in collaboration with other investigators classified 23 as deletions. Of the eight mutants analyzed here, only two produced a detectable ADH protein using the two-dimensional electrophoresis technique. Restriction endonuclease and Southern blot analysis showed that three of the mutants were normal compared to the wild-type restriction pattern, with one of the three producing a mutant ADH protein. Among the five mutants that had altered restriction patterns, only one mutant produced a detectable mutant ADH protein. All the mutants produced a hybridizable mRNA when probed with the genomic clones, suggesting that the mutant phenotype was not due to transcriptional inhibition. Two probable explanations proposed for these observations are (1) mutations may be due to deletions of one or a few bases resulting in frameshifts to nonsense codons and premature termination of ADH peptide synthesis or (2) mutations may be a result of transitions to nonsense codons, again producing shortened ADH proteins. Those mutants producing a mutant polypeptide may have resulted from mutations to missense rather than nonsense codons. The five mutants showing an abnormal endonuclease Southern blot along with the 23 mutants previously shown to be deletions (28/33 or 85%) are associated with multiple DNA chain breaks. Although all of the DNA chain breaks are not necessarily associated with the mutant phenotype of the Adh locus, multiple DNA chain breaks are the most consistent characteristic of ionizing radiation damage to DNA.

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Duarte, José Maurício Barbanti, Mariney Flávia Pereira Di Tano Ramalho, Vera Fernanda Hossepian de Lima, and Wilham Jorge. "A leukocyte cryopreservation technique for cytogenetic studies." Genetics and Molecular Biology 22, no. 3 (September 1999): 399–400. http://dx.doi.org/10.1590/s1415-47571999000300019.

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Several culture, cryopreservation, freezing and thawing methods were tested to develop an efficient technique for storing cervid and ovine leukocytes. The best results were obtained with McCoy or Vega y Martinez (VYM) solution with dimethyl sulfoxide (DMSO), horse serum and polyvinylpyrrolidone (PVP) as cryopreservatives. The best protocol for freezing was 4°C for 30 min followed by 15 min in liquid nitrogen vapor. To thaw, the still frozen material was placed onto cultivation medium for propagation.

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Lee, Hojae, Hengshi Yu, and Joshua Welch. "A beginner's guide to single-cell transcriptomics." Biochemist 41, no. 5 (October 18, 2019): 34–38. http://dx.doi.org/10.1042/bio04105034.

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Beginner's Guides each cover a key technique and offer the scientifically literate but not necessarily expert audience a background briefing on the underlying science of a technique that is (or will be) widely used in molecular bioscience. The series covers a mixture of techniques, including some that are well established amongst a subset of our readership but not necessarily familiar to those in different specialisms, or the reverse. This is our Beginner's Guide to single-cell transcriptomics.

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Browning, Heidi, Laura Berkowitz, Cynthia Madej, Janet E. Paulsen, Miriam E. Zolan, and Susan Strome. "Macrorestriction Analysis of Caenorhabditis elegans Genomic DNA." Genetics 144, no. 2 (October 1, 1996): 609–19. http://dx.doi.org/10.1093/genetics/144.2.609.

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Abstract The usefulness of genomic physical maps is greatly enhanced by linkage of the physical map with the genetic map. We describe a “macrorestriction mapping” procedure for Caenarhabditis elegans that we have applied to this endeavor. High molecular weight, genomic DNA is digested with infrequently cutting restriction enzymes and size-fractionated by pulsed field gel electrophoresis. Southern blots of the gels are probed with clones from the C. elegans physical map. This procedure allows the construction of restriction maps covering several hundred kilobases and the detection of polymorphic restriction fragments using probes that map several hundred kilobases away. We describe several applications of this technique. (1) We determined that the amount of DNA in a previously uncloned region is <220 kb. (2) We mapped the mes-1 gene to a cosmid, by detecting polymorphic restriction fragments associated with a deletion allele of the gene. The 25-kb deletion was initially detected using as a probe sequences located ~400 kb away from the gene. (3) We mapped the molecular endpoint of the deficiency hDf6, and determined that three spontaneously derived duplications in the unc-38-dpy-5 region have very complex molecular structures, containing internal rearrangements and deletions.

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James, Philip, John Halladay, and Elizabeth A. Craig. "Genomic Libraries and a Host Strain Designed for Highly Efficient Two-Hybrid Selection in Yeast." Genetics 144, no. 4 (December 1, 1996): 1425–36. http://dx.doi.org/10.1093/genetics/144.4.1425.

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The two-hybrid system is a powerful technique for detecting protein-protein interactions that utilizes the well-developed molecular genetics of the yeast Saccharomyces cerevisiae. However, the full potential of this technique has not been realized due to limitations imposed by the components available for use in the system. These limitations include unwieldy plasmid vectors, incomplete or poorly designed two-hybrid libraries, and host strains that result in the selection of large numbers of false positives. We have used a novel multienzyme approach to generate a set of highly representative genomic libraries from S. cerevisiae. In addition, a unique host strain was created that contains three easily assayed reporter genes, each under the control of a different inducible promoter. This host strain is extremely sensitive to weak interactions and eliminates nearly all false positives using simple plate assays. Improved vectors were also constructed that simplify the construction of the gene fusions necessary for the two-hybrid system. Our analysis indicates that the libraries and host strain provide significant improvements in both the number of interacting clones identified and the efficiency of two-hybrid selections.

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Savva, Christos. "A beginner's guide to cryogenic electron microscopy." Biochemist 41, no. 2 (April 1, 2019): 46–52. http://dx.doi.org/10.1042/bio04102046.

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The 'Beginner's Guides' are a new ongoing series of feature articles in the magazine, each one covering a key technique and offering the scientifically literate, but not necessarily expert audience, a background briefing on the underlying science of a technique that is (or will be) widely used in molecular bioscience. The series will cover a mixture of techniques, including some that are well established amongst a subset of our readership but not necessarily familiar to those in different specialisms. Our first 'Beginner's Guides' covers cryogenic electron microscopy.

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Sauvageau, Etienne, and Stephane Lefrancois. "A beginner's guide to bioluminescence resonance energy transfer (BRET)." Biochemist 41, no. 6 (December 2, 2019): 36–40. http://dx.doi.org/10.1042/bio04106036.

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The Beginner's Guides are an ongoing series of articles in the magazine, each one covering a key technique and offering the scientifically literate but not necessarily expert audience a background briefing on the underlying science of a technique that is (or will be) widely used in molecular bioscience. The series covers a mixture of techniques, including some that are well established amongst a subset of our readership but not necessarily familiar to those in different specialisms. This Beginner's Guide covers bioluminescence resonance energy transfer (BRET).

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Kearney, L. "Multiplex-FISH (M-FISH): technique, developments and applications." Cytogenetic and Genome Research 114, no. 3-4 (2006): 189–98. http://dx.doi.org/10.1159/000094202.

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Merkx, G. F. M., A. H. N. Hopman, A. C. M. Akkermans-Scholten, and D. F. C. M. Smeets. "Evidence for specificity of the DA/DAPI technique." Cytogenetic and Genome Research 54, no. 1-2 (1990): 62–64. http://dx.doi.org/10.1159/000132957.

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Fu, Donghui, Bi Ma, Annaliese S. Mason, Meili Xiao, Lijuan Wei, and Zeshan An. "MicroRNA-based molecular markers: a novel PCR-based genotyping technique inBrassicaspecies." Plant Breeding 132, no. 4 (April 28, 2013): 375–81. http://dx.doi.org/10.1111/pbr.12069.

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Greenwood, Hannah, Richard Edwards, and Tim Witney. "A beginner's guide to imaging in vivo tumour biochemistry." Biochemist 41, no. 4 (August 1, 2019): 42–47. http://dx.doi.org/10.1042/bio04104042.

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The Beginner's Guides are an ongoing series of feature articles in the magazine, each one covering a key technique and offering the scientifically literate but not necessarily expert audience a background briefing on the underlying science of a technique that is (or will be) widely used in molecular bioscience. The series will cover a mixture of techniques, including some that are well established amongst a subset of our readership but not necessarily familiar to those in different specialisms. This is a Beginner's Guide to imaging in vivo tumour biochemistry.

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Ball, David A., Gunjan D. Mehta, Ronit Salomon-Kent, Davide Mazza, Tatsuya Morisaki, Florian Mueller, James G. McNally, and Tatiana S. Karpova. "Single molecule tracking of Ace1p in Saccharomyces cerevisiae defines a characteristic residence time for non-specific interactions of transcription factors with chromatin." Nucleic Acids Research 44, no. 21 (August 26, 2016): e160-e160. http://dx.doi.org/10.1093/nar/gkw744.

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Abstract In vivo single molecule tracking has recently developed into a powerful technique for measuring and understanding the transient interactions of transcription factors (TF) with their chromatin response elements. However, this method still lacks a solid foundation for distinguishing between specific and non-specific interactions. To address this issue, we took advantage of the power of molecular genetics of yeast. Yeast TF Ace1p has only five specific sites in the genome and thus serves as a benchmark to distinguish specific from non-specific binding. Here, we show that the estimated residence time of the short-residence molecules is essentially the same for Hht1p, Ace1p and Hsf1p, equaling 0.12–0.32 s. These three DNA-binding proteins are very different in their structure, function and intracellular concentration. This suggests that (i) short-residence molecules are bound to DNA non-specifically, and (ii) that non-specific binding shares common characteristics between vastly different DNA-bound proteins and thus may have a common underlying mechanism. We develop new and robust procedure for evaluation of adverse effects of labeling, and new quantitative analysis procedures that significantly improve residence time measurements by accounting for fluorophore blinking. Our results provide a framework for the reliable performance and analysis of single molecule TF experiments in yeast.

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McGaugh, Suzanne E., Aaron J. Lorenz, and Lex E. Flagel. "The utility of genomic prediction models in evolutionary genetics." Proceedings of the Royal Society B: Biological Sciences 288, no. 1956 (August 4, 2021): 20210693. http://dx.doi.org/10.1098/rspb.2021.0693.

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Variation in complex traits is the result of contributions from many loci of small effect. Based on this principle, genomic prediction methods are used to make predictions of breeding value for an individual using genome-wide molecular markers. In breeding, genomic prediction models have been used in plant and animal breeding for almost two decades to increase rates of genetic improvement and reduce the length of artificial selection experiments. However, evolutionary genomics studies have been slow to incorporate this technique to select individuals for breeding in a conservation context or to learn more about the genetic architecture of traits, the genetic value of missing individuals or microevolution of breeding values. Here, we outline the utility of genomic prediction and provide an overview of the methodology. We highlight opportunities to apply genomic prediction in evolutionary genetics of wild populations and the best practices when using these methods on field-collected phenotypes.

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Chalmers, Sarah J., Stephen J. Murphy, Laura L. Thompson, Nicole L. Hoppman, James B. Smadbeck, Jessica R. Balcom, Faye R. Harris, Robert P. Frantz, George Vasmatzis, and Mark E. Wylam. "Mate-pair sequencing identifies a cryptic BMPR2 mutation in hereditary pulmonary arterial hypertension." Pulmonary Circulation 10, no. 3 (July 2020): 204589402093308. http://dx.doi.org/10.1177/2045894020933081.

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Current guidelines suggest screening all patients with idiopathic pulmonary arterial hypertension for genetic aberrations, particularly mutations in Bone Morphogenic Protein Receptor Type II ( BMPR2), the gene most commonly implicated in the pathogenesis of PAH. Herein, we present a novel technique used to identify a pathogenic germline BMPR2 alteration in a 36-year-old female and family members with hereditary pulmonary arterial hypertension who each screened negative by standard cytogenetics and molecular genetics testing.

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Khan, Shah-Naz H., and Ashfaq Shuaib. "The Technique of Intracerebral Microdialysis." Methods 23, no. 1 (January 2001): 3–9. http://dx.doi.org/10.1006/meth.2000.1101.

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Bosch, Pablo Sanchez, Julia Pepperl, and Konrad Basler. "Anchor Away – A Fast, Reliable and Reversible Technique To Inhibit Proteins in Drosophila melanogaster." G3: Genes|Genomes|Genetics 10, no. 5 (March 26, 2020): 1745–52. http://dx.doi.org/10.1534/g3.120.401055.

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Several techniques have been developed to study specific gene function in loss-of-function situations. In Drosophila melanogaster, RNAi and the generation of mutant clones are widely used. However, both techniques have the limitation that there is a significant time lag before gene function is abolished. Given the relatively rapid development of Drosophila, such perdurance is a serious impediment to study gene function. Here we describe the adaptation of the anchor-away technique for use in Drosophila. Anchor-away was originally developed in yeast to quickly and efficiently abrogate the function of nuclear proteins by sequestering - anchoring - them away in a different cellular compartment. The required components are present in the cells, and the system is triggered by the addition of rapamycin, resulting in a rapid generation of a loss-of-function situation. We provide here proof of principle for the system by producing loss-of-function situations for two nuclear proteins – Pygopus and Brinker. The system allows to study the requirement of any protein during any time window, and at the same time circumvents difficulties, such as off-target effects or variable phenotypes, which are inherent in other techniques, for example RNAi.

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Taylor, Tyl H., Darren K. Griffin, Seth L. Katz, Jack L. Crain, Lauren Johnson, and Susan Gitlin. "Technique to ‘Map' Chromosomal Mosaicism at the Blastocyst Stage." Cytogenetic and Genome Research 149, no. 4 (2016): 262–66. http://dx.doi.org/10.1159/000449051.

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The purpose of this study was to identify a technique that allows for comprehensive chromosome screening (CCS) of individual cells within human blastocysts along with the approximation of their location in the trophectoderm relative to the inner cell mass (ICM). This proof-of-concept study will allow for a greater understanding of chromosomal mosaicism at the blastocyst stage and the mechanisms by which mosaicism arises. One blastocyst was held by a holding pipette and the ICM was removed. While still being held, the blastocyst was further biopsied into quadrants. To separate the individual cells from the biopsied sections, the sections were placed in calcium/magnesium-free medium with serum for 20 min. A holding pipette was used to aspirate the sections until individual cells were isolated. Individual cells from each section were placed into PCR tubes and prepped for aCGH. A total of 18 cells were used for analysis, of which 15 (83.3%) amplified and provided a result and 3 (16.7%) did not. Fifteen cells were isolated from the trophectoderm; 13 (86.7%) provided an aCGH result, while 2 (13.3%) did not amplify. Twelve cells were euploid (46,XY), while 1 was complex abnormal (44,XY), presenting with monosomy 7, 10, 11, 13, and 19, and trisomy 14, 15, and 21. A total of 3 cells were isolated from the ICM; 2 were euploid (46,XY) and 1 did not amplify. Here, we expand on a previously published technique which disassociates biopsied sections of the blastocyst into individual cells. Since the blastocyst sections were biopsied in regard to the position of the ICM, it was possible to reconstruct a virtual image of the blastocyst while presenting each cell's individual CCS results.

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Hangan, Adriana, Gheorghe Borodi, Xenia Filip, Carmen Tripon, Cristian Morari, Luminita Oprean, and Claudiu Filip. "Structure of N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide by combined X-ray powder diffraction, 13C solid-state NMR and molecular modelling." Acta Crystallographica Section B Structural Science 66, no. 6 (November 10, 2010): 615–21. http://dx.doi.org/10.1107/s0108768110039327.

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The crystal structure solution of the title compound is determined from microcrystalline powder using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct-space methods with information from 13C solid-state NMR (SSNMR), and molecular modelling using the GIPAW (gauge including projector augmented-wave) method. The space group is Pbca with one molecule in the asymmetric unit. The proposed methodology proves very useful for unambiguously characterizing the supramolecular arrangement adopted by the N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide molecules in the crystal, which consists of extended double strands held together by C—H...π non-covalent interactions.

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Alomashi, Ghada Basil Ali, Amal Hassan Abd Al-Shabbani, and Sinan Qayes Khayoon. "Molecular identification of Hymenolepis spp. in diarrheal patients using RFLP/PCR technique for 18SS ribosomal RNA gene." Gene Reports 24 (September 2021): 101294. http://dx.doi.org/10.1016/j.genrep.2021.101294.

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Jiang, Qunyi, and Peter M. Gresshoff. "Classical and Molecular Genetics of the Model Legume Lotus japonicus." Molecular Plant-Microbe Interactions® 10, no. 1 (January 1997): 59–68. http://dx.doi.org/10.1094/mpmi.1997.10.1.59.

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The model legume Lotus japonicus was demonstrated to be amenable to classical and molecular genetic analysis, providing the basis for the genetic dissection of the plant processes underlying nodulation and nitrogen fixation. We have developed an efficient method for the sexual hybridization of L. japonicus and obtained F1 progeny derived from a cross of L. japonicus B-129-S9 Gifu × B-581 Funakura. Over half of the cross-pollinations resulted in fertile hybrid seed, which were confirmed morphologically and by single arbitrary primer DNA amplification polymorphisms using the DAF technique. Molecular and morphological markers segregated in true Mendelian fashion in a F2 population of 100 plants. Several DAF loci were linked using the MAPMAKER software to create the first molecular linkage groups of this model legume. The mapping population was advanced to generate a set of immortal recombinant inbred lines (F6; RILs), useful for sharing plant material fixed genetically at most genomic regions. Morphological loci for waved stem shape (Ssh), dark leaf color (Lco), and short flowering period (Fpe) were inherited as single dominant Mendelian loci. DAF markers were dominant and were detected between Gifu and Funakura at about one per primer, suggesting that the parents are closely related. One polymorphism (270G generated by single octomer primer 8.6m) was linked to a morphological locus controlling leaf coloration. The results demonstrate that (i) Lotus japonicus is amenable to diploid genetic analysis, (ii) morphological and molecular markers segregate in true diploid fashion, (iii) molecular polymorphisms can be obtained at a reasonable frequency between the related Gifu and Funakura lines, and iv) the possibility exists for map-based cloning, marker assisted selection and mapping of symbiotic mutations through a genetic and molecular map.

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Hilsdorf, Alexandre, Danilo Caneppele, and José Eduardo Krieger. "Muscle biopsy technique for electrophoresis analysis of fish from the genus Brycon." Genetics and Molecular Biology 22, no. 4 (December 1999): 547–50. http://dx.doi.org/10.1590/s1415-47571999000400014.

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Protein and mitochondrial DNA have been used as molecular markers to assess variability in stock identification studies of fishes. Protein and mtDNA used for electrophoretic analysis are extracted from tissues, which often leads to death of the individuals. In this study, we present a skeletal muscle biopsy procedure to extract mitochondrial DNA that does not require specimen sacrifice. Eighty pirapitinga-do-sul (Brycon opalinus) were biopsied by the present technique, with no mortalities recorded. Total DNA was extracted from muscle and digested by restriction enzymes ApaI and HpaI. The mtDNA fragment patterns were hybridized with 32P-labeled pirapitinga-do-sul mtDNA probes. The described technique is simple and may be useful in protocols requiring tissue extraction for DNA and protein analyses without loss of the individual investigated.

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Striem, M. J., G. Ben-Hayyim, and P. Spiegel-Roy. "Identifying Molecular Genetic Markers Associated with Seedlessness in Grape." Journal of the American Society for Horticultural Science 121, no. 5 (September 1996): 758–63. http://dx.doi.org/10.21273/jashs.121.5.758.

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Excluding seeded offspring at an early stage could be of great value to the breeder concerned with the development of seedless grapes (Vitis vinifera L.). We used the random amplified polymorphic DNA (RAPD) technique to identify molecular genetic markers, analyzing 82 individuals of a progeny resulting from a cross between `Early Muscat' (seeded) and `Flame Seedless'. Seven variables representing the traits of seedlessness were analyzed: mean fresh weight of one seed, total fresh weight of seeds per berry, perception of seed content, seed size categories evaluated visually, degree of hardness of the seed coat, degree of development of the endosperm, and degree of development of the embryo. Among 160 10mer primers, 110 gave distinct band patterns. Twelve markers yielded significant correlations with several subtraits of seedlessness, mainly with the mean fresh weight of one seed and the total fresh weight of seeds per berry. Multiple linear regression analysis resulted in high coefficients, such as R = 0.779 for fresh weight of seeds per berry, when the seven markers were included as independent variables in the model. Most of the seeded individuals, about 44% of the progeny, could be excluded using a two-step process of marker assisted selection.

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Šťáhlavský, František, Vera Opatova, Pavel Just, Leon N. Lotz, and Charles R. Haddad. "Molecular technique reveals high variability of 18S rDNA distribution in harvestmen (Opiliones, Phalangiidae) from South Africa." Comparative Cytogenetics 12, no. 1 (February 13, 2018): 41–59. http://dx.doi.org/10.3897/compcytogen.v12i1.21744.

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Drew, Elliot D., and Robert W. Janes. "PDBMD2CD: providing predicted protein circular dichroism spectra from multiple molecular dynamics-generated protein structures." Nucleic Acids Research 48, W1 (April 28, 2020): W17—W24. http://dx.doi.org/10.1093/nar/gkaa296.

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Abstract PDBMD2CD is a new web server capable of predicting circular dichroism (CD) spectra for multiple protein structures derived from molecular dynamics (MD) simulations, enabling predictions from thousands of protein atomic coordinate files (e.g. MD trajectories) and generating spectra for each of these structures provided by the user. Using MD enables exploration of systems that cannot be monitored by direct experimentation. Validation of MD-derived data from these types of trajectories can be difficult via conventional structure-determining techniques such as crystallography or nuclear magnetic resonance spectroscopy. CD is an experimental technique that can provide protein structure information from such conditions. The website utilizes a much faster (minimum ∼1000×) and more accurate approach for calculating CD spectra than its predecessor, PDB2CD (1). As well as improving on the speed and accuracy of current methods, new analysis tools are provided to cluster predictions or compare them against experimental CD spectra. By identifying a subset of the closest predicted CD spectra derived from PDBMD2CD to an experimental spectrum, the associated cluster of structures could be representative of those found under the conditions in which the MD studies were undertaken, thereby offering an analytical insight into the results. PDBMD2CD is freely available at: https://pdbmd2cd.cryst.bbk.ac.uk.

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Feil, Edward J., John Maynard Smith, Mark C. Enright, and Brian G. Spratt. "Estimating Recombinational Parameters in Streptococcus pneumoniae From Multilocus Sequence Typing Data." Genetics 154, no. 4 (April 1, 2000): 1439–50. http://dx.doi.org/10.1093/genetics/154.4.1439.

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Abstract Multilocus sequence typing (MLST) is a highly discriminatory molecular typing method that defines isolates of bacterial pathogens using the sequences of ~450-bp internal fragments of seven housekeeping genes. This technique has been applied to 575 isolates of Streptococcus pneumoniae and identifies a number of discrete clonal complexes. These clonal complexes are typically represented by a single group of isolates sharing identical alleles at all seven loci, plus single-locus variants that differ from this group at only one out of the seven loci. As MLST is highly discriminatory, the members of each clonal complex can be assumed to have a recent common ancestor, and the molecular events that give rise to the single-locus variants can be used to estimate the relative contributions of recombination and mutation to clonal divergence. By comparing the sequences of the variant alleles within each clonal complex with the allele typically found within that clonal complex, we estimate that recombination has generated new alleles at a frequency ~10-fold higher than mutation, and that a single nucleotide site is ~50 times more likely to change through recombination than mutation. We also demonstrate how to estimate the average length of recombinational replacements from MLST data.

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Berry, A., and M. Kreitman. "Molecular analysis of an allozyme cline: alcohol dehydrogenase in Drosophila melanogaster on the east coast of North America." Genetics 134, no. 3 (July 1, 1993): 869–93. http://dx.doi.org/10.1093/genetics/134.3.869.

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Abstract Clines may either be selectively maintained or be the by-product of nonadaptive processes related to population structure and history. Drosophila melanogaster populations on the east coast of North America show a latitudinal cline in the frequencies of two common electrophoretically distinguishable alleles at the alcohol dehydrogenase locus (Adh), designated Adh-S and Adh-F. This cline may either be adaptive or an artifact of a possible recent dual founding of North American D. melanogaster populations in which frequencies of Adh alleles differed between founder populations. By means of a high resolution restriction-mapping technique, we studied the distribution of 113 haplotypes derived from 44 polymorphic DNA markers within the Adh region in 1533 individuals from 25 populations throughout the cline. We found significant clinal differentiation at the polymorphism determining the mobility-difference causing amino acid replacement between Adh-F and Adh-S alleles. Hitchhiking was limited, despite extensive linkage disequilibrium, and other sites did not vary clinally. Such a pattern of differentiation implies that selection is responsible for the cline. To investigate whether selection acts only on the Adh-F/S site, we performed a "selective equivalence" test under the assumption that all variability within the specified allelic class is selectively neutral. This revealed selective equivalence among Adh-S-bearing haplotypes, whose frequencies showed no differentiation throughout the cline, implying high levels of frequency-homogenizing gene flow. Geographical heterogeneity among Adh-F-bearing haplotypes implied the action of selection on one or more additional variants in linkage disequilibrium with Adh-F. In a further study of a subset of the data (n = 1076 from 18 populations), we found a combined insertion/deletion polymorphism, designated delta 1, located in the 5' adult intron and in linkage disequilibrium with Adh-F, to show more marked clinal variation than Adh-F/S. Although the unequivocal identification of the precise target(s) of selection requires further study, we suggest that clinal selection may be acting epistatically on the Adh-F/S and delta 1 polymorphisms.

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Pérez-Castillo, A., M. A. Martín-Lucas, and J. A. Abrisqueta. "Evidence for lack of specificity of the DA/DAPI technique." Cytogenetic and Genome Research 45, no. 1 (1987): 62. http://dx.doi.org/10.1159/000132427.

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Journal articles on the topic 'Molecular genetics – Technique'

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