soft sweep
Hartfield M & Bataillon T 2020 Selective sweeps under dominance and inbreeding. G3:1063-1075.
- a key property of soft sweeps is that the beneficial variant is present on multiple genetic backgrounds as it sweeps to fixation
- recessive alleles can fix more easily in selfers than in outcrossers as homozygote mutations are created more rapidly
- soft sweeps from recurrent mutation or standing variation?
- sweeps arising from recurrent mutation have non–zero diversity at the selected locus
- a sweep from standing variation exhibits approximately zero diversity
- a sweep from recurrent mutation shows intermediate-frequency variants closer to the beneficial locus, compared to sweeps from standing variation
- it may be easier to differentiate between these two sweep scenarios in self-fertilizing organisms
- potential applications to self-fertilizing organisms
- a recent analysis found that soft-sweep signatures can be incorrectly inferred if analyzing genetic regions that flank hard sweeps, which was named the 'soft shoulder' effect
- due to the reduction in recombination in selfers, these model results indicate that 'soft-shoulder' footprints can arise over long genetic distances
- one remedy to this problem is to not just classify genetic regions as being subject to either a hard or soft sweep, but also as being linked to a regions subject to one of these sweeps
