Positive selection leaves a distinct signatureSchematic of haplotypes found in a population before and after a favored allele (red) is swept to fixation. There are 11 loci altogether. There are two alleles (red and gray) at the locus that was the target of selection. There are two alleles (black and gray) at each locus that is linked to the target locus. After selection, the target and some neighboring sites have all been swept to fixation.