Wednesday, June 28, 2017

DNA Testing For Genealogy – The Basics

March 23, 2010 by  
Filed under DNA Testing


With recent advances in technology and the increasing interest in tracing one’s ancestry, DNA testing for genealogy research has now become affordable and easily accessible for anyone with a computer and a mailbox. While it’s important to do your research and make sure you’re dealing with a reputable company, DNA testing kits for genealogy research are available online at a number of websites and all you have to do is mail the kit in and wait for your results.

Although DNA testing kits for genealogy research are now available to members of the public, before ordering it’s best to determine just what type of kit you’re going to need. And to do that you need to know exactly what results you’re looking for. There are two basic types of DNA testing kits available and each is used for a different reason.

mtDNA Tests – mtDNA tests are used to test the Mitochondrial DNA that is passed from the mother to both the male and female children. Mitochondrial DNA does not mix with other cells so it’s easy to determine that your mtDNA is the same as your mother’s, and your mother’s mtDNA is the same as her mother’s. Because mitochondrial DNA changes very slowly from generation to generation, it’s used best to determine the fact that you’re related to someone, as opposed to just how closely you’re related. For example, testing mtDNA can tell you if two people are members of the same family but it can’t be used to tell you if you’re brother and sister, grandfather and grandchild, etc.

If two people have an exact match in their mtDNA then there’s a good chance they have a maternal ancestor in common but it’s hard to determine if a recent ancestor or one who lived hundreds of years ago. So if all you’re trying to do is prove that your family is descended from say George Washington’s family, then yes, you could use an mtDNA test. But this test will not be able to tell you if George Washington was your grandfather.

Y Line Tests – The Y Chromosomal Test, typically referred to as the Y Line test, is only available for males since the Y chromosome is passed down the male line from father to son. Chemical markers on the Y chromosome create haplotypes, distinctive patterns that can be used to determine the genetic connection between one male and another. This test is generally used by people who have the same last name to see if the have a common ancestor. So your family could use this test to determine if the males were descended from George Washington – assuming you could also get a sample of George Washington’s DNA.

Neither of these tests can be used to gather health information or information about a predisposition to a particular disease. Nor will they allow you to create any kind of identifying personal genetic fingerprint. Rather, in most DNA testing for genealogy these tests are used to determine the line of descent and to confirm a relationship between one family and another.

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