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Male Gene Flow (male + gene_flow)
Selected AbstractsA FORMAL ASSESSMENT OF GENE FLOW AND SELECTION IN THE FIRE ANT SOLENOPSIS INVICTAEVOLUTION, Issue 2 2000Michael A. D. Goodisman Abstract., Recent studies of the introduced fire ant Solenopsis invicta suggest that introduced polygyne (with multiple queens per nest) populations are strongly influenced by male-mediated gene flow from neighboring monogyne (single queen per nest) populations and selection acting on a single locus, general protein-9 (Gp-9). This investigation formally tests this hypothesis and determines if these processes can account for the genotypic structure of polygyne S. invicta. To increase the statistical power of this test, we considered the genotypes of polygyne queens and workers at both Gp-9 and the closely linked, selectively neutral locus Pgm-3. We then constructed and analyzed a novel mathematical model to delimit the effects of monogyne male gene flow and selection on the joint genotypes at the Pgm-3/Gp-9 superlocus. Using this framework, a hierarchical maximum-likelihood method was developed to estimate the best-fitting gene flow and selection parameters based on the fit of our model to data from both the current study and an earlier one of the same population. In each case, selection on polygyne queens and workers alone, with no monogyne male gene flow, provides the most parsimonious explanation for the observed genotype frequencies. The apparent discrepancy between this result and the empirical evidence for monogyne male gene flow indicates that undocumented factors, such as other forms of selection in polygyne males or workers, are operating in introduced polygyne S. invicta. [source] Phylogeographical structure, postglacial recolonization and barriers to gene flow in the distinctive Valais chromosome race of the common shrew (Sorex araneus)MOLECULAR ECOLOGY, Issue 4 2002N. Lugon-Moulin Abstract Using one male-inherited and eight biparentally inherited microsatellite markers, we investigate the population genetic structure of the Valais chromosome race of the common shrew (Sorex araneus) in the Central Alps of Europe. Unexpectedly, the Y-chromosome microsatellite suggests nearly complete absence of male gene flow among populations from the St-Bernard and Simplon regions (Switzerland). Autosomal markers also show significant genetic structuring among these two geographical areas. Isolation by distance is significant and possible barriers to gene flow exist in the study area. Two different approaches are used to better understand the geographical patterns and the causes of this structuring. Using a principal component analysis for which testing procedure exists, and partial Mantel tests, we show that the St-Bernard pass does not represent a significant barrier to gene flow although it culminates at 2469 m, close to the highest altitudinal record for this species. Similar results are found for the Simplon pass, indicating that both passes represented potential postglacial recolonization routes into Switzerland from Italian refugia after the last Pleistocene glaciations. In contrast with the weak effect of these mountain passes, the Rhône valley lowlands significantly reduce gene flow in this species. Natural obstacles (the large Rhône river) and unsuitable habitats (dry slopes) are both present in the valley. Moreover, anthropogenic changes to landscape structures are likely to have strongly reduced available habitats for this shrew in the lowlands, thereby promoting genetic differentiation of populations found on opposite sides of the Rhône valley. [source] Y chromosome haplotyping in Scandinavian wolves (Canis lupus) based on microsatellite markersMOLECULAR ECOLOGY, Issue 8 2001A.-K. Sundqvist Abstract The analysis of mitochondrial DNA sequences has for a long time been the most extensively used genetic tool for phylogenetic, phylogeographic and population genetic studies. Since this approach only considers female lineages, it tends to give a biased picture of the population history. The use of protein polymorphisms and microsatellites has helped to obtain a more unbiased view, but complementing population genetic studies with Y chromosome markers could clarify the role of each sex in natural processes. In this study we analysed genetic variability at four microsatellite loci on the canid Y chromosome. With these four microsatellites we constructed haplotypes and used them to study the genetic status of the Scandinavian wolf population, a population that now contains 60,70 animals but was thought to have been extinct in the 1970s. In a sample of 100 male wolves from northern Europe we found 17 different Y chromosome haplotypes. Only two of these were found in the current Scandinavian population. This indicates that there should have been at least two males involved in the founding of the Scandinavian wolf population after the bottleneck in the 1970s. The two Scandinavian Y chromosome haplotypes were not found elsewhere in northern Europe, which indicates low male gene flow between Scandinavia and the neighbouring countries. [source] A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean areaANNALS OF HUMAN GENETICS, Issue 4 2001P. MALASPINA In this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications in reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny within HG 9 (Rosser et al. 2000), with the deepest branching defined by alleles T (Haplogroup Eu10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, with a high rate of male gene flow in the Turkish,Greek area. [source] | ||||||||||