Second-order moments of segregating sites under variable population size.
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.
Zivković
Daniel
D
Institut für Genetik, Universität zu Köln, 50674 Köln, Germany.
Wiehe
Thomas
T
D000465:Algorithms; D000818:Animals; D017360:Arabidopsis / Q000235:genetics*; D004171:Diploidy; D004331:Drosophila melanogaster / Q000235:genetics*; D004777:Environment; D014644:Genetic Variation; D005828:Genetics, Population; D008957:Models, Genetic; D015233:Models, Statistical; D008962:Models, Theoretical; D009154:Mutation; D011156:Population Density; D012641:Selection, Genetic