exactness of fourth (remote) cousin

[owain]

I have recently completed a family finder test. A fourth remote cousin has been thrown up and in real terms I do not know what the relationship might be. We are the same haplogroup (r- m269)on the Y side , but he is L3e3b on the maternal side - i am unsure what MT haplogroup I have. The amount of chromosomal information which we share is 45.18 (I am not sure if this is an amount or a %). I would like to know what actual relation he is to me and I would also like to know how I find my MT haplogroup. Thanks.

[John McCoy]

Family Finder does not give you your mitochondrial haplogroup -- that's a separate test. However, the mitochondrial data is relevant only to your matrilineal ancestry, because mitochondrial DNA is transmitted only from mother to child.

The relationship estimates in the Family Finder often seem wildly optimistic. On the rare occasions when I have been able to identify an exact relationship, it often turns out to be one or two generations farther removed than the estimate. The estimates should be treated as really vague suggestions, at best, for anything more remote than a first or second cousin.

Be patient! For most of us, the "right" people, the ones who happen to share the ancestors in whom we are most interested, haven't been tested yet. But now and then, a match turns up with enough genealogical information to tell us immediately who the common ancestor is. Whenever that happens, we look carefully to see if the new match helps explain any of our other, more mysterious matches.

[nicolam]

That sounds like quite a distant match, the 45.18 refers to the total number of centimorgans - cMs- you and this match have in common. You should also see what the longest block you share is. I don't think it's possible to predict exactly how you are related with the more distant matches, but 4th cousins have one set of 3xG-Grandparents in common -this link has quite a lot of info http://en.wikipedia.org/wiki/Cousin
Sorry, I don't know how to find your MT haplogroup on here, I tested at 23andMe and got the results of that at the same time as my autosomal results.

[KATM]

I see others have replied while I was writing my following "dissertation," but I'll post it anyway.

A person who matches you in Family Finder will not necessarily share either your Y or mt-DNA haplogroup. If you look at charts for Y and mt inheritance, you see they cover only a small amount of your ancestors (see the first chart on this page http://dna-explained.com/2012/10/01/...tic-genealogy/). All those in-between will have different Y and mt haplogroups than you do, but would be FF matches to you. So don't worry about the haplogroups in FF. Some will match your Y or mt haplogroup, but most won't.

The number 45.18 is in cM (centiMorgan), a measurement used for distance in a chromosome; see a better explanation here: http://www.isogg.org/wiki/Centimorgan.

45.18 cM is probably the total amount shared with this particular match. What size is the longest segment? Have you used the Chromosome Browser to see how the 45.18 cM is shared with you? If you check the chart on this page, http://www.isogg.org/wiki/Autosomal_DNA_statistics, you can see that your 45.18 cM is a bit less than the 53.13 cM that is shown for a third cousin, or 2nd cousin twice removed.

The only way you'll find out how he is related to you is to compare your research with his. FTDNA's estimate of 4th to distant might be optimistic, but it is a match of some degree of relation (I recently had an FTDNA match estimated at 4th-distant, and he turned out to be a sixth cousin, proven by paper research!). If your match really is a 4th cousin, your common ancestor may be at the 3rd great grandparent level. If he's more distant, it will be further back. You both have to have good trees developed in order to find out who the common ancestor is. Compare surnames, locations and dates.

Have you done an mt-DNA test, either at FTDNA, or somewhere else? 23andMe gives Y and mt haplogroups with their autosomal test. These are usually good, but not as complete or up to date as further testing might show. Here at FTDNA, you can take the mtDNA+ test (HV1 & HV2 regions), or the mtFullSequence (HV1, HV2, and Coding Region). The latter will give you your complete mtDNA haplogroup, while the mtDNA+ will give you your general mt haplogroup. Unless you have a genealogy problem that can be solved using mtDNA, or you are curious about your ancient maternal lines, you may not want to do an mtDNA test, though. It's not necessary to deal with your Family Finder matches.

[dna]

Let me add to the responses above.

There are two important factors that influence exactness of the predicted relationship:

• a DNA test like Family Finder compares DNA based on DNA inheritance rules, and thus cannot distinguish between a 3rd cousin twice removed and a 4th cousin (there is a nice table at http://www.isogg.org/wiki/Autosomal_DNA_statistics);
• there is large variability in the amount of DNA one is getting from parents. DNA does not come evenly from parents! Please take a look at the following website!!! http://www.thegeneticgenealogist.com...ect-an-update/

W. (Mr.)

[LadyAlaise]

So how many cMs would a potential Half Aunt and or a Half Uncle potentially share with me??

[dna]

So how many cMs would a potential Half Aunt and or a Half Uncle potentially share with me??

According to the link I had posted, people found values from 540.1 cM to 1348 cM.

[LadyAlaise]

Wow! Good to know~ thanks!

[jsarnacki]

According to the link I had posted, people found values from 540.1 cM to 1348 cM.

And to add to this, my three kid's share 238.99, 476.87, and 494.33 cM with their half great-aunt! This woman is their grandma's half-sister. As you can see, siblings can vary quite a bit! My kids are full siblings by the way! My daughter shares much less DNA with this woman than either of my sons.

[sshayward]

Known 4th cousin

I have recently completed a family finder test. A fourth remote cousin has been thrown up and in real terms I do not know what the relationship might be. We are the same haplogroup (r- m269)on the Y side , but he is L3e3b on the maternal side - i am unsure what MT haplogroup I have. The amount of chromosomal information which we share is 45.18 (I am not sure if this is an amount or a %). I would like to know what actual relation he is to me and I would also like to know how I find my MT haplogroup. Thanks.

Through our Family Finder results we identified a 4th cousin and his shared CM was only 20.58. I identified him through the surnames and realized I had communicated with him years ago while conducting research. We have 3rd G-grandparents in common. It really showed the credibility of the results and the match showed up on my sibling's results as well.

I believe it will take a considerable amount of research to determine if I can confirm relationships with those who have larger CM matches.