Alloway and Southern Ayrshire FAMILY HISTORY SOCIETY Robert Burns Cottage, Alloway, Ayr
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Wednesday, 22 September 2010

21 Sep 2010 - "DNA and Genealogy"

At our first meeting of the new season, Chris Paton, who is a professional genealogist and writes for magazines such as "Practical Family History" and "Your Family Trees", gave a most interesting and informative talk on DNA and Genealogy. We all tried to understand the science - honest...

Tackling a very complex and technical subject, Chris described the 3 types of DNA test currently available for genealogical purposes:

  • Y chromosome DNA (Y-DNA) passed along the male line, similar to surnames
  • Mitochondrial DNA (Mt-DNA) passed along the female line
  • Autosomol DNA which we all inherit from both parents
The test most likely to be useful is of the Y-DNA. Chris described how Marker points, stretched along the Y-chromosome, give the personal DNA signature or list of numbers that are similar for common male ancestors. The greater the numbers in common, the closer the relationship, or time to the most recent common ancestor. He explained the way the tests can be used to assist family history researchers and went on to dispel some of the hype that implies that the use of DNA tests will immediately solve all family history problems.

He illustrated how Y-DNA tests can sometimes disprove family myths or resolve uncertain paternity, due to illegitimacy or adoption for example.  By comparing two male descendants' Y-DNA, the probability of them belonging to the same patrilineal line can be assessed.  Within the Scottish Clan system it has been used to show that male descendants having the same Clan name may not actually belong biologically to the Clan, but may have adopted the Clan name because they lived in the Clan territory or to pledge fealty.

The Mt-DNA, on the other hand, can be used to connect the maternal lines of living people and, because it is more stable with less mutation, only provides clues to deep ancestry, e.g. links to early human migration, so is of little help with recent events.

The autosomol DNA is inherited from both parents so is of use only within a few generations. Using this, people of different gender can be tested to assess the probability that they are biologically related.

Chris recommended the book "Family History in the Genes" by Chris Pomery published by the National Archives for anyone wanting to find out more and he can be contacted through his website or see his blog at

We all now know a little more about this new tool and now we can reassess our brick walls and family legends.

Patricia Weston

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