The Genetic Genealogist

AncestryByDNA is a popular genetic test developed by DNAPrint Genomics, Inc. The company offers a variety of genetic testing, including Y-chromosome and mtDNA ancestry. They are most well-known, however, for their two admixture tests. Admixture tests examine SNPs, or single nucleotide polymorphisms, in the 22 autosomal chromosomes in each of our cells. Although every human’s DNA is 99.9% identical, the 0.1% differences make each one of us unique. Researchers have noticed that people in a particular region often have a mutation in common, one that people in most or all other regions of the world do not have. These usually harmless mutations, called SNPs, are believed to have bio-geographic properties – people endogenous to certain regions of the world have different versions of the SNPs. A person who submits his DNA for analysis could have SNPs which reveal genetic contributions from a wide variety of regions.

Admixture tests have many caveats. For instance, inheritance of autosomal DNA is completely random and no test can accurately predict your entire heritage. With every generation an ancestor’s DNA contribution can be passed down in its entirety, in part, or not at all. As well, many scientists are still debating whether or not SNPs have the bio-geographic properties that make admixture tests possible. What if the SNP that is supposedly unique to Native Americans has also developed in a large but undetected European population? The test would misconstrue that SNP as being Native American rather than European.

Despite a number of concerns, admixture tests are becoming increasingly popular and huge resources are being poured into admixture research by a number of different companies. The tests will undoubtedly only increase in popularity and thus become even more accurate and informative. With low-cost genome sequencing just around the corner, this field will explode in the next 5 to 15 years. You can expect to hear much more about admixture tests and genealogy.

The AncestryByDNA 2.5 test examines 175 SNPs (Version 2.0 only offered 71 markers). The test reveals percentages for the following four regions - Native American (North, South, and Central America); European (European, Middle Eastern, and the Indian subcontinent); East Asian (Japanese, Chinese, Korean, Pacific Islander); and African (Sub-Saharan African as well as Nigeria and Congo regions). The results of the test are given as percentages for each group.

AncestryByDNA also offers the EuroDNA 1.0 test. This test, only available to people that have taken the company’s other test and revealed at least 50% European ancestry, uses 145 additional SNPs to delineate European ancestry into four groups – Northern European, Southeastern European, Middle Eastern, and South Asian.

DNAPrint Genomics recently completed a project with five middle school classes at the Laboratory School of Finance and Technology in the Bronx. The project involved analysis of DNA from 11 students and one teacher.