Biology:Genetic admixture

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Short description: Result of interbreeding between two or more previously isolated populations within a species


Genetic admixture occurs when previously isolated populations interbreed resulting in a population that is descended from multiple sources. It can occur between species, such as with hybrids, or within species, such as when geographically distant individuals migrate to new regions. It results in gene pool that is a mix of the source populations.[1][2][3]

Examples

Climatic cycles facilitate genetic admixture in cold periods and genetic diversification in warm periods.[4] Natural flooding can cause genetic admixture within populations of migrating fish species.[5] Genetic admixture may have an important role for the success of populations that colonise a new area and interbreed with individuals of native populations.[6]

Mapping

Admixture mapping is a method of gene mapping that uses a population of mixed ancestry (an admixed population) to find the genetic loci that contribute to differences in diseases or other phenotypes 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.[7]

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.[8] By 2010, high-density mapping panels had been constructed for African Americans, Latino/Hispanics, and Uyghurs.

See also


References

  1. Korunes, Katharine L.; Goldberg, Amy (2021-03-11). "Human genetic admixture". PLOS Genetics (Public Library of Science (PLoS)) 17 (3): e1009374. doi:10.1371/journal.pgen.1009374. ISSN 1553-7404. 
  2. Rius, M.; Darling, J.A. (2014). "How important is intraspecific genetic admixture to the success of colonising populations?". Trends in Ecology & Evolution 29 (4): 233−242. doi:10.1016/j.tree.2014.02.003. PMID 24636862. 
  3. Yang, Melinda A.; Fu, Qiaomei (March 2018). "Insights into Modern Human Prehistory Using Ancient Genomes". Trends in Genetics 34 (3): 184–196 6y. doi:10.1016/j.tig.2017.11.008. PMID 29395378. 
  4. "Disjunct distribution and distinct intraspecific diversification of Eothenomys melanogaster in South China". BMC Evolutionary Biology 18 (1): 50. 2018. doi:10.1186/s12862-018-1168-3. PMID 29636000. 
  5. Jaisuk, C.; Senanan, W. (2018). "Effects of landscape features on population genetic variation of a tropical stream fish, Stone lapping minnow, Garra cambodgiensis, in the upper Nan River drainage basin, northern Thailand". PeerJ 6: e4487. doi:10.7717/peerj.4487. PMID 29568710. 
  6. "Admixture determines genetic diversity and population differentiation in the biological invasion of a lizard species". Biology Letters 4 (4): 434−437. 2008. doi:10.1098/rsbl.2008.0205. PMID 18492644. 
  7. Shriver, MD (April 2003). "Skin pigmentation, biogeographical ancestry and admixture mapping". Human Genetics 112 (4): 387–99. doi:10.1007/s00439-002-0896-y. PMID 12579416. 
  8. Winkler, C. A.; Nelson, G. W.; Smith, M. W. (2010). "Admixture mapping comes of age". Annu Rev Genom Hum Genet 11: 65–89. doi:10.1146/annurev-genom-082509-141523. PMID 20594047. PMC 7454031. https://zenodo.org/record/1234977. 

Further reading