"The bird was completely relaxed in my presence, looking at me inquisitively with one eye and then with ... I remember thinking that this is natural selection in action, here before my eyes ...

Today, with access to heretofore unprecedented data sets for the study of human genetic variation, researchers can exploit the genetic signatures of natural selection using novel analytical methods.

Aa Aa Aa Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population ...