Admixture, as defined in genetics, is the identification of groups of SNPs that come from some earlier population. Likely isolated and interbred for several generations to make the "signature" unique to them. Admixture analysis is what results in the ethnicity pie charts popular with the genetic genealogy testing companies and mostly focuses on using the atxDNA results. This study is more concerned with regional origins in a more recent time period where haplogroup and phylogenetic trees are more focused (traditionally) on ancient populations and migrations. But this is evolving.
This has been a developing science from population genetics simply because (a) there has not been widespread enough testing to truly uniquely identify clusters of SNPs to particular populations and (b) it relies on testing current individuals and surmising their genetic heritage / background. But great strides have been made of recent outside the academic setting by the genetic genealogy testing companies like Ancestry and 23andMe due to their large databases of testers. So much so that Ancestry is actually tracking clusters to immigrants and time periods in North American colonization. And 23andMe has been identifying DNA clusters down to not just a country but county districts within countries. Some of this was likely spurred by LivingDNA starting from some seminal research work on identifying clusters within U.K. counties.
This has been a developing science from population genetics simply because (a) there has not been widespread enough testing to truly uniquely identify clusters of SNPs to particular populations and (b) it relies on testing current individuals and surmising their genetic heritage / background. But great strides have been made of recent outside the academic setting by the genetic genealogy testing companies like Ancestry and 23andMe due to their large databases of testers. So much so that Ancestry is actually tracking clusters to immigrants and time periods in North American colonization. And 23andMe has been identifying DNA clusters down to not just a country but county districts within countries. Some of this was likely spurred by LivingDNA starting from some seminal research work on identifying clusters within U.K. counties.
External References
- Strider, Daniel, "Overview of Admixture Mapping", Curr Protoc Hum Genet. 2013 Jan; CHAPTER: Unit1.23. oi: 10.1002/0471142905.hg0123s76
- Khan, Razib, Analyzing ancestry with admixture, step by step, Discover Magazine, 14 Mar 2011 (utilizing the http://software.genetics.ucla.edu/admixture/UCLA Admixture tool)
- Wikipedia Genetic Admixture