soft sweep

Pokalyuk C 2012 The effect of recurrent mutation on the linkage disequilibrium under a selective sweep. J Math Biol 64:291-317.

• hard sweeps dominate for θ_s < 0.01
• both hard sweeps and soft sweeps occur in the range 0.01 < θ_s < 1
• for θ_s > 1, almost all adaptive substitutions will result in soft sweeps

• in Drosophila melanogaster there should exist many soft sweeps due to tremendous short-term effective population sizes relevant for adaptation
• ongoing research argues for the importance of soft sweeps and polygenic adaptation
• tests based on haplotype structure have higher power to detect soft sweeps