Second-order moments of segregating sites under variable population size

Genetics. 2008 Sep;180(1):341-57. doi: 10.1534/genetics.108.091231. Epub 2008 Aug 20.


The identification of genomic regions that have been exposed to positive selection is a major challenge in population genetics. Since selective sweeps are expected to occur during environmental changes or when populations are colonizing a new habitat, statistical tests constructed on the assumption of constant population size are biased by the co-occurrence of population size changes and selection. To delimit this problem and gain better insights into demographic factors, theoretical results regarding the second-order moments of segregating sites, such as the variance of segregating sites, have been derived. Driven by emerging genomewide surveys, which allow the estimation of demographic parameters, a generalized version of Tajima's D has been derived that takes into account a previously estimated demographic scenario to test single loci for traces of selection against the null hypothesis of neutral evolution under variable population size.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Animals
  • Arabidopsis / genetics*
  • Diploidy
  • Drosophila melanogaster / genetics*
  • Environment
  • Genetic Variation
  • Genetics, Population
  • Models, Genetic
  • Models, Statistical
  • Models, Theoretical
  • Mutation
  • Population Density
  • Selection, Genetic