Assessing human variation data for signatures of natural selection

In this article, we highlight some of the different types of natural selection, their effects on patterns of DNA variation, and some of the statistical tests that are commonly used to detect such effects. We also explain some of the relative strengths and weaknesses of different strategies that can be used to detect signatures of natural selection at individual loci. These strategies are illustrated by their application to empirical data from gene variants that are often associated with differences in disease susceptibility. We briefly outline some of the methods proposed to scan the genome for evidence of selection. Finally, we discuss some of the problems associated with identifying signatures of selection and with making inferences about the nature of the selective process.