Genetic Diversity, Population Structure and Wolbachia Infection Status in a Worldwide Sample of Drosophila melanogaster and D. simulans Populations

Abstract

Drosophila melanogaster and its close relatives have been extremely important model species in the development of population genetic models that serve to explain patterns of diversity in natural populations, a major goal of evolutionary biology. A detailed picture of the evolutionary history of these species is beginning to emerge, as the relative importance of forces including demographic changes and natural selection is established. A continuing aim is to characterise levels of genetic diversity in a large number of populations of these species, covering a wide geographic area. We have used collections from five previously un-sampled wild populations of D. melanogaster and two of D. simulans, across three continents. We estimated levels of genetic diversity within, and divergence between, these populations, and looked for evidence of genetic structure both between ancestral and derived populations, and amongst derived populations. We also investigated the prevalence of infection with the bacterial endosymbiont Wolbachia. We found that D. melanogaster populations from Sub-Saharan Africa are the most diverse, and that divergence is highest between these and non-Sub-Saharan populations. There is strong evidence for structuring of populations between Sub-Saharan Africa and the rest of the world, and some evidence for weak structure amongst derived populations. Populations from Sub-Saharan Africa also differ in the prevalence of Wolbachia infection, with very low levels of infection compared to populations from the rest of the world.

Prevalence and genotypic diversity of the symbiotic bacterium Wolbachia in the Drosophila melanogaster population of Nalchik

“…Comparing the obtained data with the results of research, which was conducted for the natural populations of D. mela nogater of the world (Hoffmann et al, 1994(Hoffmann et al, , 1998Solignac et al, 1994;Ilinsky andZakharov, 2007a, 2007b;Ilinsky, 2008;Nunes et al, 2008;Verspoor and Haddrill, 2011;Richardson et al, 2012;Ilinsky, 2013) can lead to the conclusion that this level does not differ from the infection level typical for the natural popula tions of Eurasia.…”

“…The studies concerning the distribution of symbi otic bacterium Wolbachia in the natural populations of D. melanogaster of the world showed that this bacte rium is found everywhere with the average infection frequency of populations of 50% (Hoffmann et al, 1994;Solignac et al, 1994;Ilinsky andZakharov, 2007a, 2007b;Ilinsky, 2008;Verspoor and Haddrill, 2011). New data have appeared on the distribution and geno typic diversity of Wolbachia in the natural populations of D. melanogaster in Eurasia (Riegler et al, 2005;Ilinsky andZakharov, 2007a, 2007b;Ilinsky, 2008;Nunes et al, 2008;Richardson et al, 2012;Ilinsky, 2013).…”

“…Endosymbiont Wolbachia, which is widespread in D. melanogaster populations through out the world. The occurrence frequency of a bacte rium can vary widely: from single infected specimens to entirely infected populations, but on average it is about 50% (Hoffman et al, 1994(Hoffman et al, , 1998Solignac et al, 1994;Ilinsky andZakharov, 2007a, 2007b;Ilin sky, 2008;Nunes et al, 2008;Verspoor and Haddrill, 2011;Richardson et al, 2012;Ilinsky, 2013).…”

Estimation of the Spontaneous Mutation Rate per Nucleotide Site in aDrosophila melanogasterFull-Sib Family

“…A D. melanogaster full-sib family was produced by crossing individuals from isofemale lines derived from a population collected in Ghana in January 2010 (Verspoor and Haddrill 2011). A single male and female parent taken from different lines were allowed to mate for 3 days and then separated.…”

Coevolution of Drosophila melanogaster mtDNA and Wolbachia Genotypes

“…However, some populations have an extremely low frequency of infected individuals, e.g. a population from West Africa sampled in 2010, that had only one infected individual in a sample of over hundred flies [11].…”