Ancestry DNA Testing 25 Jun 2019
Riff, Resolve, Repeat0
Genetic ancestry testing is a method by which one arrives at additional family genealogical information that goes far beyond anecdotal or historical data. Meticulously examining DNA variations can provide valuable clues surrounding one’s ancestors, family relationships, and even certain patterns of genetic variation. There are three principal types of ancestry DNA testing.
The first is Y chromosome testing. When there are variations in Y chromosomes, such as those passed from father to son, the variations can be used to look further into the direct male line. This can only be done on males as females do not have a Y chromosome. The most common reason for a Y chromosome test outside of general curiosity is to see whether two families with the same last name are related.
A second type of ancestry testing is mitochondrial DNA testing. Most DNA is packed tight into chromosomes within the cell nucleus, and cell structures (mitochondria) contain a small amount of DNA (belonging exclusively to them). Women and men have mitochondrial DNA that is passed on by their mothers. As opposed to Y chromosome testing, mitochondrial DNA testing provides additional information on the direct female line. A huge benefit here is many female ancestral lines can end up lost over time due to the elimination of the women’s last name post marriage. Mitochondrial DNA testing rescues this historical record.
The third, most frequently implemented test is the single nucleotide polymorphism test. This will evaluate several variations of single nucleotide polymorphisms (SNPs) considering a person’s entire genome. After the results are in, they are then compared with others who have also taken the test to compare ethnic backgrounds. For example, you might take this test and discover you are 40 percent Asian, 20 percent European, 35 percent African and 5 percent unknown. A Y chromosome and mitochondrial DNA test only represent single ancestral lines and cannot compare individual ethnic backgrounds with others. This is valuable for those who either want to figure out their exact background, test for potential health hazards that might be common to certain ethnicities, and on a more practical side, really know how your ethnic make-up can affect things like university or employment applications.
On a personal note, your humble scribe knew of someone who went through this test and discovered a significant amount of his ethnic background was Native American. He was then told that for college applications in California at the time, preference was being given for applicants to certain programs who could demonstrate Native American ancestry. He of course applied and was later accepted. Had it not been for this test, he would never have known for sure.
Now, like anything, genetic ancestry testing has its limitations. The providers of said tests will compare individual test results to various tests from distinct databases (of previous tests) so depending on the provider the ethnicity estimates will likely vary from one provider to another. This means that if you are receiving this test from one provider, using that same provider to furnish complementary, contextual information is critical. You also need to factor in that we as humans have migrated frequently over time and mixed even more frequently with many different ethnic groups. All these permutations over time make this an ever-evolving science.