The Role of DNA in Birth Family Searches

>> Thursday, February 23, 2012

Many adoptees who had exhausted other avenues for finding birth families, have been turning to DNA testing. The science is still new but can give important clues as to one's heritage. In additional to identifying people who are different degrees of "cousin" matches, it also can give the adoptee information on ethic heritage as well.

The two largest DNA companies for this purpose are FTDNA and 23andme. For this, it is beneficial to have a company that has a lot of tests recorded so that your DNA can be matched with as many others as possible. Recent tools have been developed that let you use the information from one of these services in the other. Since each service checks on on different markers, the results will be different and a comparison the two sets of results can be beneficial. 

After testing and getting results joining a forum, such as the yahoo group AdoptionDNA can be helpful as advice is freely shared among members of the group.

As more testing is done, your results are updated so over time you get more and more information. Either of these services can advise you as to what tests you should get.

You will expect to see results come back with indications of 2nd, 3rd, 4th cousins, etc. Also important is the length. Regarding FTDNA results, both the TOTAL amount of shared DNA and the LONGEST BLOCK are important, but it is the longest block that is more indicative of a more recent connection.  For example, a person could have lots of little pieces of shared DNA, depending on how DNA combines over many years-many generations, but not any large shared block, so the most recent common shared ancestor may not be as recent. A larger shared block of DNA means a more recent shared common ancestor.  Usually a longest shared block of over 10-12.cM is considered most significant for considering a closer common connection. 

There are a number of online tutorials to help you understand how this works and the folks on the forum will also help guide you through this. 

Exploring these relationships is a lot of work, but when you have no more information, it is another avenue to explore.


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