DNA testing is most often used to prove relationships like paternity or maternity. However, DNA testing is also proving to be an unexpected boon to genealogy. Ancestry DNA testing is possible because some parts of the DNA that is passed from one generation to the next remains unchanged. This provides a link to generations past and helps reconstruct family histories.
There are limits to ancestry DNA testing. It doesn’t quite serve up an entire family tree or help you find your ancestors. It does however tell you if you are related to people with the same surname, it can help prove or disprove family tree research you’ve already done, and it can give you some clues about your ethnic origin. Ancestry DNA testing has been possible for some time now, but only recently have costs fallen far enough to place it within reach of average individuals.
Ancestry DNA testing is possible using two basic methods. The first is mitochondrial DNA (mtDNA) testing. Mitochondrial DNA is contained in the cytoplasm of the cell. It is passed from the mother to her offspring without mixing. Your mtDNA is the same as your mother’s, which is the same as her mother’s, and on down the line. If two mtDNA samples match, then there is a very good chance that they share a common maternal ancestor. Unfortunately the test doesn’t specify whether the ancestor is recent or one who lived centuries ago. Males receive mtDNA from their mother, but do not pass it on to their children.
The Y chromosome in DNA can also be used in ancestry DNA testing. Also known as Y DNA or Y-Line DNA, Y chromosomal DNA testing can only be done for males. The Y chromosome is passed from father to son only. Each Y chromosome is marked by a distinctive pattern called a haplotype. Male lineages can be distinguished by these different haplotypes. If the haplotypes match, it indicates that there is some degree of relatedness between the subjects, but the relationship is not exactly specified. Y chromosome ancestry DNA testing is most often used to find out if individuals with the same surname share a common ancestor.
Beyond specific genealogical questions, ancestry DNA testing can provide more general revelations about your ethnic origins. Several DNA laboratories offer ancestry DNA testing to determine estimated percentages of ancestry from four major groups: Native American, Indo-European, East Asian or African. If your ancestry DNA testing indicates a high percentage of European ancestry, it’s possible to test further to determine specific European heritage.
Recent developments in the realm of ancestry DNA testing include new testing methods to compare DNA fingerprints using STR DNA analysis, which is the most common forensic testing method. This type of ancestry DNA testing compares your unique DNA fingerprint to a database of DNA fingerprints and matches your DNA to one of nineteen different world regions.