Would a DNA test confirm a late 18th century connection?

[Pennie]

For a number of years I've been corresponding with someone in Australia - we're both researching the same (very unusual) surname.

His maternal grandmother and my maternal grandmother both share this surname.

Tracing this surname back through our respective trees (three generations in his case and four in mine), we come to two individuals living in neighbouring London parishes and with the same occupation.  There are also several other "circumstantial" connections between these two.

Whilst I've been able to continue tracing my direct line of this surname back to the late 16th century, he has been unable to take his line any further as we can't find any details of his 3 x great-grandfather's parentage.

However, given the rarity of the surname, we both feel that it is highly likely that we both descend from the same family and I'm wondering if there's any sort of DNA/genetic testing that would help us to prove/disprove this?

Any guidance would be most welcome - thank you.

Pennie

[davidft]

Yes I think this is something DNA (autumnal DNA) testing may be able to help with. However you may need to test more than the two of you to give more helpful results.

If there is three generations in your case and four in your correspondents case then any common ancestor is going to be further back. The good news is that a grandchild shares 25% of their DNA with their grandparent and a great grandchild 12.5% with their great grandparents. Even allowing for a common ancestor being a generation or two back that still means they could share 6.25% or 3% DNA with the common ancestor. Where this comes into play is when you have had your DNA tested and put it in a site like Gedmatch.com you can look at the chromosome browser and not only does it tell you on which chromosome you match but where about on it, i.e. is it a strong match or just a match that is no more than "noise". Gedmatch also has a facility to tell you if your parents were related which may also be of use.

One word of caution, you inherit genes at random, even two siblings do not inherit exactly they same genes from their parents and so this may complicate things a little. And thus this is why you may need to test some others as well to make the results more robust.

So dependent on what others have to say I would say give it a go it may help you.

Good luck

[medpat]

I had my DNA analysed with 23andMe. I was linked to an American who knew his paternal grandparents were English. We exchanged e-mails and he named his grandfather. Luckily I had his grandfather already in my tree.

The American's great, great, great grandmother was my great, great, great grandmother's sister - we therefore share our 4th gt grandparents born 1790 and 1794. He was down as one of my closest relatives.

Hope this helps