What *Proves a kinship?

[Kay Martin]

We have five men in our group with a proven relationship by DNA and good to circumstantial paper evidence. One of these gentleman has two (one step) mutations at 389-1 and 389-2, but his paper trail is good. All carry the same surname. Now we have found a gentleman of a different surname but with a 23 marker match out of 25 - the mutations being one step at 390 and 385a. This man's family has known connections to the first surname, however. Does this DNA find prove relationship? Should we be looking for an adoption / step parent / whatever? Thanks!

[mark price]

Please see your personal page within the Family Tree DNA Web site; at the bottom you will find a new link we have recently added that deals with undertsanding matches with different surnames.

Hopefully you will find this useful!

[Kay Martin]

Mark, thanks. I was on that page when your reply came in!

While I understand now that two men of different surnames could have a 23/25 match (or greater?) and yet not be related, I would like to see some statistical figures eventually that would narrow all of this down. It's easy enough to see that Joe Smith in England and John Jones in the US probably are not related even tho they have a reasonably close match of DNA scores. But what if Joe Smith and John Jones had families from the same small town in Virginia during the same time period? It seems to me that many factors would come into saying if there is a possible relationship beside a common surname or a documented paper trail -- knowing that if the DNA pointed to a relationship the researcher would need to then find the paper trail if at all possible.

Kay

[mark price]

Give this a try: go to the front page of the ftdna Web site. Click on the title "Enough Markers?"

From there access Dr. Bruce Walsh's page featuring his writings on The Most Recent Common Ancestor. This article is laden with a plethora of the statistics that it sounds like you are searching for.

I hope you find this helpful!

[gaamccj]

Re: What *Proves a kinship?

Originally posted by Kay Martin
We have five men in our group with a proven relationship by DNA and good to circumstantial paper evidence. One of these gentleman has two (one step) mutations at 389-1 and 389-2, but his paper trail is good. All carry the same surname. Now we have found a gentleman of a different surname but with a 23 marker match out of 25 - the mutations being one step at 390 and 385a. This man's family has known connections to the first surname, however. Does this DNA find prove relationship? Should we be looking for an adoption / step parent / whatever? Thanks!

if a brother and sister both had families
what would his grandaughter be to her grandson?

[Jim Barrett]

They would be second cousins.

[gaamccj]

Re: Re: What *Proves a kinship?

Originally posted by gaamccj
if a brother and sister both had families
what would his grandaughter be to her grandson?

the brother and sisters kids would be cousins
but what would her grandchild be to his grandchild

and is there any real connection any more?
blood cousins???

[Kay Martin]

Second cousins. This is an area where both siblings descendants could need the others. If the brother had a son who had a son, that grandchild would carry his Grandfather's Y-DNA. If the sister had a daughter who also had a daughter, that girl would carry her Grandmother's mtDNA.

But to carry your question a little further. If the grandchildren have children, those kids would be 3rd cousins to each other. The brother and sister are siblings, their children are first cousins, their grandchildren are second cousins, their great grandchildren are third cousins, etc. They are all related by blood and all could be potentially useful to building your famlies DNA "tree".

Kay