I’ve searched for a definition of
signature of natural selection. Unfortunately, I haven’t found any formal definition of it.
The signature of positive selection on standing genetic variation. I found this post that links to an article measuring the signature with an Fst and a Linkage Disequilibrium test.
Are we looking at only some frequency of alleles in different populations? Is the signature only a fixation of alleles in a population where this allele was positively selected?
Another article says:
A single beneficial substitution can be detected in polymorphism data, so long as it occurred recently. The fixation of a favorable allele in a population distorts patterns of variation at linked sites, thereby leaving a distinguishing signature that lasts up to about 104 generations in humans or about 106 in Drosophila melanogaster (Przeworski 2002). In principle, targets of positive selection can therefore be identified by searching polymorphism data for regions that harbor this signature (Nair et al. 2003; Wright et al. 2005).
Is it always in linkage disequilibrium?