DNA is now an essential tool for the family historian. It can be used to test hypotheses about relationships and can sometimes provide answers that can’t be found in the paper trail alone. The databases are growing at a phenomenal rate, the cost of testing has plummeted in the last few years, and DNA testing is now so much more affordable.
An autosomal DNA test from AncestryDNA, Family Tree DNA or 23andMe can be taken by both males and females and will put you into a matching database to connect you with genetic cousins on all the different branches of your family tree. Although these tests can provide matches with more distant cousins, they are best used for making connections within the last five or six generations.
The traditional Y-chromosome DNA and mitochondrial DNA tests can also help with your genealogy research.
The Y-chromosome is passed on by a man to his sons and the transmission usually corresponds with the inheritance of surnames. If you have two males with the same surname a Y-DNA test will tell you whether or not they share a common ancestor. Y-DNA tests can also help with brick walls as a result of illegitimacy or adoption.
Both men and women have mitochondrial DNA, but only women can pass on mtDNA to the next generation, so this test follows an all-female path of inheritance. mtDNA tests are less useful because the surname changes with each generation. It also has a slow mutation rate, which means that the matches can be very distant, but it can be useful in some situations.
To read the full article and find out more about DNA tests and who to test with, read Family Tree November!