How the worm turns the genic world

In the middle years of the last decade there were many papers which came out which reported many 'hard' selective sweeps reshaping the human genome. By this, I mean that you had a novel mutation arise against the genetic background, and positive selection rapidly increased the frequency of that mutation. Because of the power and rapidity of the sweep many of the flanking regions of the genome would "hitchhike" along, generating long homogenized regions of linkage disequilibrium. If that's a little dense for you, just understand that very strong selective events tend to result in disorder and distinctiveness in the local genomic region. But the late aughts and the early years of the teens are shaping up give us a more subtle picture. Instead of classic hard sweeps, researchers are suggesting that there may also be many 'soft' sweeps, where selection draws upon the well of standing genic variation. Instead ...