I have just been contacted by my seventh cousin seeking information about her family.
It’s a kind of warm fuzzy feeling talking with a very distant relative on another continent.
But, it struck me, how closely are we really related?
OK we share a pair of ancestors in eighteenth century England, so we should share one half to the power of eight (IIRC) of our genes. That’s quite small really.
Now, how relevant is this blood relationship?
Given a relatively constant gene pool in the England of the sixteenth-nineteenth century, how much of my gene make-up is similarly close to any other non-related person descended from English ancestors over the same period of time?
The two Presidents Roosevelt - Theodore and Franklin - were fifth cousins. Elenor was also related to TR (grand-niece or something), so FDR and Elenor were related and still married. Granted, 5th or more cousins is still pretty out there, but it still makes you go “Hmmm…”
My wife and I met in college. She was from Boston, half-Italian and half English (her mother is from England). I am Southern all the way with only British Isles ancestry but my ancestors all came over very early starting at the 1st Colony at Jamestown (where I got my name).
There was always one weird thing about my wife and I. We apparently look alike according to the thousand or so people that have told us that since we started going out.
We had a daughter last summer that came down with one of the rarest genetic diseases in the world at 6 days old (Sulfite Oxidase Deficiency; 50 cases reported worldwide.) It is an extremely genetic disease and the geneticists concluded that we have to be related in some way and it must come from England. I am trying to find a common link.
How’s that for a bite in the ass. You marry someone with a completely different background from 1800 miles away and you turn out to be 7th cousins or something and somehow both got these rare genes.
Eleanor was TR’s brother’s daughter. Which produces a highly interesting bit of trivia: FDR was the most recent President to get married in the White House. Since ER’s father was dead at the time of their marriage, TR gave her away at the wedding, which he hosted at the White House while President.
7th cousins: Out of your 256 6xgreat grandparents, you and your 7th cousin shared 2 of them. Assuming no other cross-lineages, etc. Your share 0.78% of your ancestry.
I missed the replies to this thread when my computer died. Thanks for that answer. Next question: in a relatively homogenous population, say white anglo-saxons in the UK, what percentage of my ancestry would I share with a random member of that same group.
This was the nub of the question that I was getting at. Do I have any rational reason for feeling more genetically realted to ny seventh cousin than to a random member of the same general gene pool?
Wow, a blast from the past. I did a double-take on seeing my post. I read it before I realized that I wrote it!
No, you’re really no more related to that person than you are to a random member of your own gene pool, assuming you mean your community where your family has resided for a century or 3.
But then you might feel slightly closer to them if it’s you and your cousin, both of basque ancestry, amidst a bunch of australian aborigines. Slightly.
Frankly, there’s not that much difference in the human genome from group to group. Breeding with your 7th cousin would be no more of a risk than with a random ‘unrelated’ person.
Or so I recall reading back when I studied human genetics. Can’t find a cite right now.
