Interpreting your DNA matches

Some of your comments have indicated a need for guidance in interpreting your DNA matches.  In our next release, we’ll be including some educational material that will assist with this activity.  In the meantime, here are three good starting questions to help you decipher if a potential match is a good candidate.  In evaluating a potential Y match, ask these questions: 

1. On how many markers were each of the participants tested?
2. How many markers do the participants share in common, or on how many markers do the participants differ?
3. Is there a common surname? 

It is important when reviewing your match list that you and the other participant (match candidate) were tested on the majority of markers, Y46.  The number of markers acts similarly to a phone number.  An area code e.g. 12 markers, yields a large pool of individuals sharing that same 3 digit code.  A prefix (33 markers) refines you to an even tighter group of people and so on.  If you do have a match with a person tested at only 12 markers, for example, you may want to contact the individual, discuss the situation and encourage an upgrade to see if there is still a significant match with that participant with a higher resolution test.  

Next, you want to make sure that you match on all but two or three markers.  A most recent common ancestor (MRCA) number will tell you how related you are to your match.  It is a statistical analysis that takes into account the number of markers and the mutation rates, but it is meant to be used only as a guide.  Its purpose is to help you think about how many generations may separate you from a direct link to your potential match. 

Lastly, evaluate the surnames.  If you were tested on the majority of markers and do not differ by more than a few marker values, yet the surname is different, there could have been an adoption, illegitimacy or name change.  So, go ahead and contact the potential match and collaborate on determining where a common ancestor is shared. 

Y DNA and mtDNA differ not only in their inheritance patterns, their usefulness in genealogy vs. anthropology, the associated laboratory processes, but also within deciphering among potential matches.  For instance, mtDNA is a great ancient ancestry tool, but its near-ancestry (recent genealogy) value is not as great as is the Y DNA.  mtDNA is, however, helpful in targeted instances where you have a specific hypothesis you are testing.  If the results of the participants do NOT match, then you can conclude that the individuals do NOT share a common maternal ancestor; if, however, they do match you can NOT conclude that the do share a common maternal ancestor since many people will share the same mtDNA results.  Therefore, the correct “interpretation” is that you share common ancient maternal ancestry.

Some people connect instantly; others as the database grows.  Ancestry.com DNA will notify you of a potential Y match if that person is within 7 generations.  It is with the marriage of DNA and traditional paper genealogy that will show where and whom the actual common paternal ancestor is.  Should you ever have any questions about your matches or results, please contact our client services team at dna@ancestry.com.