Adaptive evolution of genes involved in the regulation of germline stem cells in Drosophila melanogaster and D. simulans.
Bottom Line: Population genetic and comparative analyses in diverse taxa have shown that numerous genes involved in reproduction are adaptively evolving.Two genes involved in germline stem cell regulation, bag of marbles (bam) and benign gonial cell neoplasm (bgcn), have been shown previously to experience recurrent, adaptive evolution in both Drosophila melanogaster and D. simulans.Here we report a population genetic survey on eight additional genes involved in germline stem cell regulation in D. melanogaster and D. simulans that reveals all eight of these genes reject a neutral model of evolution in at least one test and one species after correction for multiple testing using a false-discovery rate of 0.05.
Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853.Show MeSH
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Mentions: There have been several genome-wide, next-generation sequencing surveys of variation in D. melanogaster and D. simulans that have reported departures from an equilibrium neutral model in directions consistent with natural selection for GSC-related gene ontology categories or at/near several GSC genes (Begun et al. 2007; Langley et al. 2012; Pool et al. 2012). It remains informative to examine specific genes, particularly using parallel assays on population data from both D. melanogaster and D. simulans. Here, we report high-quality Sanger resequencing from population samples of both species for eight genes involved in GSC regulation (cyclin A, mei-P26, nanos, P-element induced wimpy testis (aka piwi), pumilio, stonewall, fs(1)Yb, and zero population growth), test for evidence of selection using polymorphism-based methods and reanalyze longer-term sequence evolution at these genes using phylogenetic analysis by maximum likelihood (PAML). These eight genes include those whose products genetically and/or physically interact with bam and/or bgcn and are likely to have shared functions, and those that appear to have non-bam/bgcn-related roles in GSC regulation. Figure 1 illustrates the roles of these loci within the female germline, wherein the functions and interactions of these genes are more thoroughly understood. We note that several of these genes function somewhat differently in the male germline (Fuller and Spradling 2007; Gilboa and Lehmann 2004; Gonczy et al. 1997; Insco et al. 2009; Kawase et al. 2004; Song et al. 2004).
Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853.