 | This articlemay be too technical for most readers to understand. Pleasehelp improve it tomake it understandable to non-experts, without removing the technical details.(January 2023) (Learn how and when to remove this message) |
Genetic admixture occurs when previouslyisolated populations of organisms interbreed, resulting in a population with genetic ancestry from both sources. It can occur between species, such as withhybrids, or within species, such as when geographically distant individuals migrate to new regions. It results in a population with genetic backgrounds, or agene pool, that is a mix of the source populations.[1][2][3] Genetic admixture is recognized as an important contributor to rapid evolutionary responses, both at the level ofgene flow between populations and between species.[4]
Climatic cycles facilitate genetic admixture in cold periods and genetic diversification in warm periods.[5]Naturalflooding can cause genetic admixture within populations of migrating fish species.[6]Genetic admixture may have an important role for the success of populations that colonise a new area andinterbreed with individuals of native populations.[7] Similarly, climate-associated genetic variants may move more quickly by admixture than background variation across the genome.[8]
Admixture mapping is a method ofgene mapping that uses apopulation of mixed ancestry (an admixed population) to find the geneticloci that contribute to differences in diseases or otherphenotypes found between the different ancestral populations. The method is best applied to populations with recent admixture from two populations that were previously genetically isolated. The method attempts to correlate the degree of ancestry near a genetic locus with the phenotype or disease of interest. Genetic markers that differ in frequency between the ancestral populations are needed across the genome.[9]
Admixture mapping is based on the assumption that differences in disease rates or phenotypes are due in part to differences in the frequencies of disease-causing or phenotype-causing genetic variants between populations. In an admixed population, these causal variants occur more frequently on chromosomal segments inherited from one or another ancestral population. The first admixture scans were published in 2005 and since then genetic contributors to a variety of disease and trait differences have been mapped.[10] By 2010, high-density mapping panels had been constructed for African Americans, Latino/Hispanics, andUyghurs.