Editing Genetic drift (section)

===Random effects other than sampling error===

Random changes in allele frequencies can also be caused by effects other than [[sampling error]], for example random changes in selection pressure.<ref>{{harvnb|Li|Graur|1991|p=28}}</ref>

One important alternative source of [[Stochastic#Biology|stochastic]]ity, perhaps more important than genetic drift, is [[genetic hitchhiking|genetic draft]].<ref name="gillespie 2001">{{cite journal | vauthors = Gillespie JH | title = Is the population size of a species relevant to its evolution? | journal = Evolution; International Journal of Organic Evolution | volume = 55 | issue = 11 | pages = 2161–9 | date = November 2001 | pmid = 11794777 | doi = 10.1111/j.0014-3820.2001.tb00732.x | publisher = [[John Wiley & Sons]] for the [[Society for the Study of Evolution]] | s2cid = 221735887 | author-link = John H. Gillespie | doi-access = free }}</ref> Genetic draft is the effect on a [[Locus (genetics)|locus]] by selection on [[genetic linkage|linked]] loci. The mathematical properties of genetic draft are different from those of genetic drift.<ref>{{cite journal | vauthors = Neher RA, Shraiman BI | title = Genetic draft and quasi-neutrality in large facultatively sexual populations | journal = Genetics | volume = 188 | issue = 4 | pages = 975–96 | date = August 2011 | pmid = 21625002 | pmc = 3176096 | doi = 10.1534/genetics.111.128876 | publisher = Genetics Society of America | arxiv = 1108.1635 }}</ref> The direction of the random change in allele frequency is [[autocorrelation|autocorrelated]] across generations.<ref name="Masel 2011" />