11/10/2023 0 Comments Gene flow definition![]() A considerable body of work is dedicated to the inference of gene flow, and several software packages exist. Wakeley 2009 discussed gene flow exclusively in the coalescence framework. The online text Felsenstein 2013 introduced gene flow from a mathematical viewpoint and also included a more modern treatment of gene flow in the context of coalescence theory. Chapters in Gillespie 2004, Hartl and Clark 1997, and Hedrick 2000 reviewed gene flow in terms of standard population genetics theory based on allele frequencies without delivering in-depth analysis of the topic. The basics of migration/gene flow are treated prominently in all population genetics textbooks. Slatkin 1985 reviewed the effects of gene flow on variability within populations. Many fields in biology use the concept of gene flow routinely as a general characterization of the data gathered, leading to a large literature using measurements of gene flow and a considerable literature proposing new measures and comparisons of measures. The improvement of detection of genetic differences led to a large number of new methods to estimate the magnitude of gene flow. Since 1990, microsatellite and DNA sampling methods have replaced the original allozyme-based approaches. In 1982, a theoretical breakthrough arrived with the formal description of coalescence theory, which sparked development of many inference methods based on finite mutation models and complex population models. These techniques permitted the first studies of genetic variation within and between natural populations of plants and animals and commonly used analyses during this time were based on allele frequencies. Technical advances between 19 allowed the characterization of enzyme variants (allozymes) that were treated as products of different genetic alleles. Its early usage was most commonly theoretical in nature because, except for breeding experiments, the inheritance of characters from parents to offspring was poorly understood: only the phenotypes were available for study. Discussions of gene flow started shortly after the definition of population genetics in the early 1900s, although the term itself first appeared in 1941. This article treats gene flow and migration, as used in population genetics, equivalently. ![]() In practice, the terms migration and gene flow are equivalent in population genetics, although in other fields, such as ecology, migration may mean instead seasonal migration. ![]() These results suggest that the adaptive value of inversions is maintained, regardless of the lack of genetic differentiation within arrangements from different populations, and thus favors the Local Adaptation hypothesis over the Coadapted Genome hypothesis as the basis of the selection acting on inversions in these populations.In population genetics, both gene flow and migration assume that individuals arrive from other localities gene flow also assumes that such individuals can successfully mate with locals and may produce offspring with mixed inheritance, whereas migration does not require potential mixing of genetic material. However, high levels of gene flow were detected for all six genes when comparing the same arrangement among populations. Despite the extensive gene flux detected outside the inverted region, significant genetic differentiation between both arrangements was found inside it. The six analyzed genes (Pif1A, Abi, Sqd, Yrt, AtpĪ± and Fmr1) were selected for their location across the O-chromosome and their implication in thermal adaptation. Our sampling focused on two frequent O-chromosome arrangements that differ by two overlapping inversions (OST and O(3+4)), which are differentially adapted to the environment as observed by their opposing latitudinal clines in inversion frequencies. Here we analyze levels and patterns of nucleotide diversity, selection and demographic history, using 37 individuals of Drosophila subobscura from Mount Parnes (Greece) and Barcelona (Spain). Many chromosomal inversions are under strong selection and their role in recombination reduction enhances the maintenance of their genetic distinctness. Gene flow (defined as allele exchange between populations) and gene flux (defined as allele exchange during meiosis in heterokaryotypic females) are important factors decreasing genetic differentiation between populations and inversions.
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