Strange transatlantic DNA match(?) from 18th century

[Huwcyn]

I recently noticed a match for my surname as being 'good' (Roughly 70%) in a 4th-6th cousin range.
31 of my ggg-grandparents were rural Welsh, but the 32nd  (Ralph Chambers b 1783 (?)- d 1818 St Pancras)gave my my surname - Chambers. The lady to whom I was matched is American, and has traced her family back to much the same number of generations as I have. None of her ancestors were Welsh, as far as one can see, but her gggg-grandmother (1783 - 1865) was a Mary Ann Chambers. This lady seems to have been born in the United States.

Can anyone please explain how likely it is that Ralph and Mary Ann Chambers were of the same family, please ? I don't really understand the genetics part. All plausible theories welcome.

[davidft]

I recently noticed a match for my surname as being 'good' (Roughly 70%) in a 4th-6th cousin range.

I was a bit intrigued by this as to be honest it does not mean anything to me therefore please may I ask if you could explain it a bit more as that may help.

I am assuming from what you wrote this is from a test done by Ancestry and it is not on any other test site, is that correct?

[familydar]

Hi Huwcyn

How confident are you of your tree and how confident is your American DNA match with hers?  Have you seen her tree?  If not then see if she will send you a link to it (if online) or email you a GED.

If neither of you have been able to find parents for Ralph or Mary Ann then there's the possibility that one or other of them might be the illegitimate child of a soldier (I assume that the military were criss-crossing the Atlantic at that time).

If both of your trees stack up, and Ralph and Mary Ann aren't illegitimate, and we rule out the possibility that the same individual/couple didn't have families both sides of the Atlantic, then the MRCAs can't be any closer than the grandparents of your Ralph and her Mary Ann.  That pushes the "cousinship" out beyond 6th cousin, so probably just coincidence.

Can I suggest that if you've not already done so, you do a free upload of your AncestryDNA results and tree to both FTDNA and GEDMatch, that way you will get matches to people who've tested with other companies and you'll also get some more analysis tools to play with.

Jane :-)

[Huwcyn]

re : 18: 45.  It is an 'Ancestry' test, yes. A bar is attached to each ' match' for a person, suggesting either '4th-6th' cousinage , or ' 5th - 8th' distant cousinage. The bar is set at around 70% full (described as 'High') for my 'cousin' match with this lady.

re : 19:24. I am about 80% confident of my tree 1750-1800, 95% confident  1800 onwards. A lot of my family history was 'known' and written down prior to my research starting, on all four grandparents' sides. A lot of DNA matches have come up for transatlantic cousins who were known about, certainly on my mother's side. In that respect, its helped them more than its helped me. I've seen the other person's tree, and no obvious link to Wales or Welsh surnames occur anywhere. The one thing I cannot rule out is cuckoldry, of course. Were Mary Ann and Ralph brother and sister, then this lady would be a sixth cousin to my children. What would be shown were one illegitimate and they were half-brother/sister ?
    I think a maritime connection would be likelier than a military one - (post 1776 ! ) .
Thank you very much indeed for the tip re uploading the results elsewhere. I'd not realised that this was possible.

[familydar]

quick reply because busy day ahead

DNA for half siblings would manifest itself as roughly half of the DNA match you'd espect for full siblings (so 4th cousin pushed out to 5th cousin etc).

Using mirror trees on Ancestry, "in common with" on FTDNA and the "people who match one or both" tool on GEDMatch you should be able to use your known transatlantic cousins for triangulation, might help decide whether the two CHAMBERS people are along the same line or not.

Jane :-)