Species-wide genetic variation and demographic history of Drosophila sechellia, a species lacking population structure
Autor: | Delphine Legrand, Daniel Lachaise, Maud I. Tenaillon, Marie-Louise Cariou, Justin Gerlach, Pat Matyot |
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Rok vydání: | 2009 |
Předmět: |
animal structures
Demographic history Population Molecular Sequence Data Biology Investigations Polymorphism Single Nucleotide Drosophila sechellia Evolution Molecular Effective population size Species Specificity Molecular evolution Genetic variation Genetics Animals education education.field_of_study Base Sequence Models Genetic Population size fungi Genetic Variation Bayes Theorem biology.organism_classification Genetics Population Evolutionary biology Drosophila Approximate Bayesian computation |
Zdroj: | Genetics. 182(4) |
ISSN: | 1943-2631 |
Popis: | Long-term persistence of species characterized by a reduced effective population size is still a matter of debate that would benefit from the description of new relevant biological models. The island endemic specialist Drosophila sechellia has received considerable attention in evolutionary genetic studies. On the basis of the analysis of a limited number of strains, a handful of studies have reported a strikingly depleted level of genetic variation but little is known about its demographic history. We extended analyses of nucleotide polymorphism in D. sechellia to a species-wide level using 10 nuclear genes sequenced in 10 populations. We confirmed that D. sechellia exhibits little nucleotide-sequence variation. It is characterized by a low effective population size, >10-fold lower than that of D. simulans, which ranks D. sechellia as the least genetically diverse Drosophila species. No obvious population subdivision was detected despite its fragmented geographic distribution on different islands. We used approximate Bayesian computation (ABC) to test for demographic scenarios compatible with the geological history of the Seychelles and the ecology of D. sechellia. We found that while bottlenecks cannot account for the pattern of molecular evolution observed in this species, scenarios close to the null hypothesis of a constant population size are well supported. We discuss these findings with regard to adaptive features specific to D. sechellia and its life-history strategy. |
Databáze: | OpenAIRE |
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