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General => Ancestral Family Tree DNA Testing => Topic started by: SuzyWoo on Friday 11 May 18 07:57 BST (UK)
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Hi, I have been trying to get my head around the 5th to 8th cousins matches that have come up on Ancestry. I have got about 300 pages of them!!
When I read the help section it gave me this information:
"As far as DNA goes, you do have a fair amount of shared DNA with this match, however the relationship is distant if it exists at all.".
I understand that the relationship with these cousins is distant but the above seems to indicate that they may not be related to me at all.
Could someone shed any light on this for me please.
Many Thanks
Sue :D
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As I understand it, your closest matches in 5th to 8th cousin range are perhaps likely to be definitely connected to you, and with full trees on both sides, you might be able to confirm the match.
The further down the list you go, the less likely it is to be a) a genuine match and/or b) a confirmable match. If you click through to your last few pages, you are likely to share as little as 6cM with them. This can sometimes mean a false positive match, sometimes a very distant match. 5th to 8th cousins indicates possible 4G to 7G grandparents, and perhaps a generation or so before that. I haven't traced all of my 7G and 8G grandparents - I've got further back than that on a few lines, not so far on a few more. Add in the likelihood of your match knowing all of their 7G and 8G grandparents as fairly remote, if they even have an online tree.
You may strike lucky and you both have the same surname from the same small village. You may be unlucky - where you match could be the one great grandparent of some degree that you haven't been able to trace, or one of the 512 7G grandparents of some degree that your match has been unable to trace, or any other combination.
Or the match could be coincidental, IBS rather than IBD.
The lowest confirmed match I have found is of 6.7 cM with a 4th cousin twice removed. Many more follow her, as I said before down to 6 cM.
You just have to work away at them, bit by bit.
Regards Margaret
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Margaret,
Thankyou for your explanation it certainly helps to have it explained in more detail.
Regards
Sue :)
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Sue, There are also 'common pile up areas' to be taken into consideration.
This, I believe, is where DNA passes down almost unchanged from one generation to the next, perhaps for many generations. You might share 6 or 7 cMs with them, but it could from, say, a 10, 11, 12 or even more distant G grandparent. Unlikely ever to find where you match.
Start painting matches chromosome details into GedPainter or similar, you will find lots of matches in these areas, tempting to think they are all related to you and each other, but they aren't either.
https://cruwys.blogspot.co.uk/2018/01/small-segments-and-pile-ups.html
Regards Margaret
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After spending a lot (i.e. far too much) time on my Ancestry DNA match list, I now look only at 5th to 8th cousins that are described as "Good" on the page. About half a dozen new results are added each week that are "Good" or better and I like to stay on top of them.
You might also click on the little "i" button next to the "Good". This will tell you the total length of matching segments and how many segments are matched. Ancestry lists matches in descending order of total length so its will rank 21.5 cM as better than 21.4 cM even though the latter might be one single strand whilst the former might be three strands of about 7 cM each.
I have one example where I found the test uploaded to Gedmatch and worked out that two of the three matched segments were indeed in "pile up zones" and therefore statistically insignificant.
As I consider each newly-published match, I note the total length and number of segments in the "Add note" area on the results page.
I readily admit that there are plenty of potential useful moderate matches but somehow I can't create the thirty-three hour day to deal with them!
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I don't look at many of my 5 to 8 matches initially.
I use the surname and place search to find more remote connections. Wish it would work consistently though.
Margaret