READER Q AND A
WE DON'T MATCH OUR 3RD COUSIN...
HARRY: I have recently come across a descendant of a brother of my great-great grandmother. He is on Ancestry and My Heritage, but I do not match with him, neither do two known cousins on My Heritage. I appreciate that fourth cousins only have 50% chance of matching. Would it be worth accessing his DNA matches on Ancestry?
KAREN:
You’re absolutely right – second cousins and closer should always match but after that there is a percentage chance there will be no/too little shared DNA. There is a chart (right) from the International Society of Genetic Genealogy (ISOGG) Wiki that shows the percentage chance of a match.
If the descendant of your 2x greatgrandmother’s brother will be happy to share his DNA matches then that will give you the opportunity to find cousins who don’t share enough DNA with you on that side of the family but are genealogically related. It’s nice to have other family to test but not always possible – I have lots of aunts/uncles who have tested but I bemoan the fact all my grandparents are gone! It’s a very addictive hobby!
WHO & WHERE TO TEST?
STEPHEN: Can you advise on the most appropriate company to buy a test from? I have been researching my wife’s ancestry for many years and have come up against a brick wall. She has a direct female ancestor born c.1795 who has her place of birth noted on different census as both Gloucestershire and Ireland. There is very strong circumstantial evidence to suggest she was Irish but absolutely no conclusive documentary evidence. My wife has no interest in finding living relatives, any medical side of any test or anything other than exploring the potential Irish connection.
Is there a particular company that you would suggest for such a seemingly basic task? Would her elderly mother be a better subject of the test to go back another generation and eliminate her natural father’s DNA?
KAREN: Your best option is to test your wife’s mother. Testing the oldest generation possible will not only ‘remove’ the paternal matches but you will be genetically one step closer to the ancestor of interest.
You don’t say how many generations ago the ancestor is but I’m presuming she is fewer than five generations away from your mother-in-law. Autosomal DNA tests such as Ancestry are most accurate at finding DNA up to five generations back, but the further they are the less ‘obvious’ matches might be to that one particular ancestor.
The test will give you two areas – the matches and ethnicity estimate. If you use just the ethnicity estimate to establish the Irish link then it would be inconclusive. Your mother-in-law’s test may well show/ not show an Irish connection, but it would not prove if the particular ancestor you are interested in was Irish. Ethnicity estimates cover 500-1,000 years ago, so any of your wife’s maternal side could have been of Irish descent. As an example, my mom’s ethnicity shows 14% Scottish yet I have been able to trace her side up to the 18th century on all sides and none were from further north than Stoke on Trent! Ethnicity estimates are estimates.
Matches work by showing common DNA between living people. So, if your motherin-law had a match who you could see was descended from the brother of the ancestor in question then you would have an idea you were on the right track.
You do not need to contact or approach matches. It is then down to the basic family research you have been used to doing. How does this match’s tree line up with the one I have? Which matches indicate the ancestor you’re interested in?
Personally, I would test with one of the two companies who do not accept uploads, that is Ancestry and 23andme. Once you have the test you can upload
(if happy with terms and conditions) to other sites, looking for more matches – Myheritage, Familytreedna, Gedmatch and Livingdna all accept uploads which could produce potential matches to the ancestor in question.
Best of luck in your research!