soft sweep
Hermisson J & Pfaffelhuber P 2008 The pattern of genetic hitchhiking under recurrent mutation. Electron J Prob 13:2069-2106.
- a soft sweep has highly characteristic features, such as a more pronounced pattern of linkage disequilibrium as compared to a hard sweep
- soft sweeps can arise in several biological scenarios
- multiple copies of the beneficial allele can already segregate in the population at the start of the selective phase
- adaptation from standing genetic variation
- most naturally, however, the mutational process at the selected locus itself may lead to recurrent introduction of the beneficial allele
- for biological applications the most important question is: When are soft sweeps from recurrent mutation likely?
- the probability of soft selective sweeps is mainly dependent on the population-wide mutation rate θ
- the classical results of a hard sweep are reproduced in the limit θ → 0 and generally hold as a good approximation for θ < 0.01 in samples of moderate size
- for larger θ, approaching unity, soft sweep phenomena become important
