October 27, 2021

DNA in Genealogy

A story hit the papers last weekend which highlights the growing importance of DNA testing to genealogy. Whilst we are familiar with DNA testing in criminal cases or to legally prove parentage, its use for genealogical purposes is perhaps lesser known.

Kevin Percy, an antiques dealer from New Zealand has claimed that he is the rightful heir to the Duke Of Northumberland’s estate which includes Alnwick Castle. Ralph Percy, the 12th Duke, has dismissed the claim saying “It is not unusual to hear such claims, as they crop up every few years”. But with around 50,000 hectares of land, an estate valued in the 100’s of millions and an hereditary title at stake perhaps he might take it more seriously.

Kevin Percy wants two bodies exhumed that he believes carry  the Louvain-Percy bloodline which was thought to have died out in 1670 when the 11th Earl died with no male heir. He wants DNA testing to be carried out which will prove (or disprove) that he is a direct descendant of this line and thus the rightful heir.

It is the “Y” chromosone which determines paternal ancestry as this is passed on from father to son and only occurs in males.¬† Evidently there are only 18 major paternal lineages and testing can determine broad geographical region of origin which can be narrowed down through further testing.

The two other possible DNA tests that can be carried out are mitochondrial DNA which is passed from a mother to her children (male and female) and autosomal DNA which is passed from both parents to all children.

Thus mitochondrial testing can determine the female line whilst autosomal testing can help identify close ancestry as it is made up of the DNA of parents, grandparents, great-grandparents and so on.

A number of companies are now offering DNA testing specifically for genealogical purposes and so at less cost than legally binding testing. One of these is GeneTree.com who offer all the types of test mentioned above.

I doubt most of us will find ourselves contesting hereditary titles but DNA testing may well become an important tool in discovering more of our ancestry.

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