Tuesday, 26 December 2017


I'm by no means an expert in the use of DNA in genealogy.  As a professional genealogist, however, I am trying to learn as much as I can about the subject.

On the face of it, it seems a wonderful idea - take a quick and easy DNA test to find out who your ancestors were without all the hard work of doing your tree.  There are so many stories about adoptees who have found their birth families as a result of taking a genealogical DNA test and it is now relatively cheap to do so.

DNA tests - the reality check


The reality is of course a little different.  Most companies offer you a broadbrush view of your ethnicity and a matching service with other DNA samples which have been submitted BUT if your close match has not tested with that company then you will not find them.  You can download your results in the form of "raw data" and submit them to another site such as GEDMatch to widen your search  but for most of us struggling to get to grips with the matches we already have this may as yet be a step too far.

One thing becomes very clear as you get your first matches - you do need to have already done quite a lot of documentary research already in order to establish your joint ancestor.  In general the longer the matching sections of common DNA you have with a possible match the closer the relationship BUT if your ancestry largely consists of people from a fairly small geographical area who have intermarried for generations those assumptions of closeness are skewed.  That common ancestor may be a lot further back than indicated!

AND if your matches are anything like mine the link is probably in that line you haven't yet researched thoroughly or where you have hit a brick wall.

DNA Ethnicity estimates

As for the ethnicity estimates - that is exactly what they are - ESTIMATES - and they can vary and be updated further along the line as more samples are added to the database.  My daughter and I both tested with Living DNA which does not as yet offer DNA matching but does offer a more detailed breakdown by region for UK ancestry.  In general both sets of results fit fairly closely with the documentary evidence and in fact have presented a few areas for further research on MY tree as there seems to be a bit of West Country ancestry I had not foreseen.  (When it appeared in my daughter's results I had ascribed it to my mother in law's ancestry.)

Would I recommend taking a DNA Test?


Yes on the whole I would recommend it  BUT

  • DO get your tree in order first as without a tree to check your matches are pretty useless
  • DO check out the privacy policies of the company you intend to use
  • DO learn at least the basics of DNA for genealogy before you start - there are plenty of webinars and videos about it on Youtube for instance
  • DO treat the ethnicity estimate as just that - an estimate


  • DON'T expect  miracles or immediate matches
  • DON'T offend your siblings who have different results to yours - the DNA mix we inherit from our parents is unique to ourselves and siblings may have a different mix
  • DON'T become a DNA bore - it can be very technical and most people really don't want to hear the details
  • DON'T be upset if the ethnicity estimate throws up something unexpected.  So many different ancestors contributed to the mix we inherit and that unforeseen result may lead to exciting discoveries when you follow it up with documentary research.



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