[Paleo Conservative]

This is so much hooey.

I would say that the DNA "results" are highly suspect.

Why couldn't it be accurate?

If you assume 25 year generations, ten generations back you have 1,024 (2¹⁰) ancestors 250 years ago. If you go back twenty generations, you have 1,048,576 (2²⁰) ancestors 500 years ago. At thirty generations you have 1,073,741,824 (2³⁰) ancestors 750 years ago. In just 33 generations (825 years), you have more ancestors than there are people living today.

[null and void]

Neglecting cousins marrying cousins, and restricted gene pools in isolated villages, of course...

[KarlInOhio]

If you assume 25 year generations, ten generations back you have 1,024 (210) ancestors 250 years ago....

Unless you're a lurker from DU, in which case you're lucky to have a dozen ancestors from 10 generations back. And a few of those are farm animals.

[IronJack]

And at some point all ancestry converges. But we know that certain genotypes beget certain phenotypes, and we identify those phenotypes as characteristic of certain races. Presumably, the underlying genotypes dominate in the identified pool, and people are interested in finding out where that dominant pool is.

No doubt we all have some strain of Mongolian midget or three-legged Castillian courtier in us too, but it is wrong to assume that they are anything but vestigial contributions.

Unless you happen to be short, a good rider, and a deadeye with a bow and arrow. Or Spanish.

[Paladin2]

....1,073,741,824 (2**30)....

There may have been inbreeding in your family, but definitely not in mine. ;-)

[patton]

Your analysis contains an assupmtion that they are disjoint sets - which, in my case, at least, is patently untrue.

[GoLightly]

Besides the math you've laid out, consider the way our DNA replicates. If you are a male, your paternal grandfather's Y & your father's Y are usually identical to your own Y. These mail order kits are only a small snapshot.

I read somewhere that we actually carry the genes of ancestors in the low double digits, so going back many generations you're actually looking to find out which ancestors *possibly* contributed toward your own genetic makeup.

[DejaJude]

Why couldn't it be accurate?
If you assume 25 year generations, ten generations back you have 1,024 (210) ancestors 250 years ago. If you go back twenty generations, you have 1,048,576 (220) ancestors 500 years ago. At thirty generations you have 1,073,741,824 (230) ancestors 750 years ago. In just 33 generations (825 years), you have more ancestors than there are people living today.

The thing is, DNA testing is new. That would mean they are testing people that live in those areas now. We know that we have been migrating for centuries. I would also like to know what percentage of the population they are testing. Or are they only testing ancient bones?

[MamaB]

My late husband said if you go back far enough we are all related. I have 42 generations in my FTM with 1905 surnames. The earliest date is 733 but it is not my direct line.

Does anyone use FTM? If so, FReepmail me. I have a question but I can not find the answer in the book.