Turner TL, Stewart AD, Fields AT, Rice WR, Tarone AM. Population-based resequencing of experimentally evolved populations reveals the genetic basis of body size variation in Drosophila melanogaster.
PLoS Genet 2011;
7:e1001336. [PMID:
21437274 PMCID:
PMC3060078 DOI:
10.1371/journal.pgen.1001336]
[Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 02/14/2011] [Indexed: 01/08/2023] Open
Abstract
Body size is a classic quantitative trait with evolutionarily significant variation within many species. Locating the alleles responsible for this variation would help understand the maintenance of variation in body size in particular, as well as quantitative traits in general. However, successful genome-wide association of genotype and phenotype may require very large sample sizes if alleles have low population frequencies or modest effects. As a complementary approach, we propose that population-based resequencing of experimentally evolved populations allows for considerable power to map functional variation. Here, we use this technique to investigate the genetic basis of natural variation in body size in Drosophila melanogaster. Significant differentiation of hundreds of loci in replicate selection populations supports the hypothesis that the genetic basis of body size variation is very polygenic in D. melanogaster. Significantly differentiated variants are limited to single genes at some loci, allowing precise hypotheses to be formed regarding causal polymorphisms, while other significant regions are large and contain many genes. By using significantly associated polymorphisms as a priori candidates in follow-up studies, these data are expected to provide considerable power to determine the genetic basis of natural variation in body size.
Understanding the causes and consequences of natural genetic variation is crucial to the characterization of biological evolution. Moreover, natural genetic variation is comprised of millions of perturbations, which are partially randomized across genotypes such that a small number of individuals can be used to combinatorially analyze a large number of differences, facilitating mechanistic understanding of biological systems. Here we demonstrate a powerful technique to parse genomic variation using artificial selection. By selecting replicate populations of Drosophila flies to become bigger and smaller, and then determining the evolutionary response at the genomic level, we have mapped hundreds of genes that respond to selection on body size. As our approach is powerful and cost-effective compared to existing approaches, we expect it to be a major component of diverse future efforts.
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