Recent and ongoing selection in the human genome

Abstract

Genes or genomic regions that are under selection will typically be functionally important and will often be disease associated. They are, therefore, of interest not only to evolutionary biologists, but also to researchers in the fields of functional genomics and disease genetics. Both negative selection acting against deleterious mutations and positive selection acting in favour of beneficial mutations is common in the human genome. Although most selection acting on segregating mutations in disease genes is negative selection — acting against deleterious, predominantly recessive mutations — some mutations in complex diseases might also have been affected by positive selection in the past or present. Several genome-wide scans for loci that are under selection have been carried out. These scans have provided a large amount of new information, but have also generated controversy as the concordance between results is not always high. The main reason for the lack of concordance is probably that different tests differ in their power to detect different forms of selection. However, statistical problems relating to assumptions about demography, recombination and ascertainment biases can also affect the results of some studies.