Soft Shoulders Ahead: Spurious Signatures of Soft and Partial Selective Sweeps Result from Linked Hard Sweeps

摘要: Characterizing the nature of adaptive process at genetic level is a central goal for population genetics. In particular, we know little about sources substitution or number variants currently segregating in nature. Historically, geneticists have focused attention on hard-sweep model adaptation which de novo beneficial mutation arises and rapidly fixes population. Recently more has been given to soft-sweep models, alleles that were previously neutral, nearly so, drift until such time as environment shifts their selection coefficient changes become beneficial. It remains an active difficult problem, however, tease apart telltale signatures hard vs. soft sweeps genomic polymorphism data. Through extensive simulations hard- here show indeed two might not be separable through use simple summary statistics. it seems recombination regions linked to, but distant from, sites can create patterns closely mirror what expected found near sweeps. We find very similar situation when using haplotype-based statistics are aimed detecting partial ongoing selective sweeps, distinguish shoulder sweep from center sweep. While knowing location selected site mitigates this problem slightly, stochasticity natural will frequently cause signal reach its zenith far effect severe sweeps; thus inferences target well mode positive may inaccurate. addition, both since ends biologically realistic levels allelic gene conversion lead errors classification identification This general “soft shoulders” underscores difficulty differentiating scenarios molecular genomics The soft-shoulder also implies common recent evolutionary history, prevalent spurious appear some genome-wide scans.