Genetic Study Tracing Mankind's Ancient Travels

Has anyone else participated in one of these studies?

[BluffTHIS!]

How ancient? We each have approximately 100K genes I believe, and after so many generations, like 100, you start dropping genes from some of your ancestors. Thus even if you could be certain you were descended from a particular person back that far, you might not actually possess any of his genes. So this factor would limit such a study to some small degree although of course all of your genes are inherited from even further back. Also from what I have read, there are limitations on determining the ethnicity of one's ancestors going back very far, and that would be key in determing travel patterns. Perhaps some poker playing geneticist will chime in here and elaborate.

[benkahuna]

I've studied genetics a bit, certainly enough to address your question.

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Thus even if you could be certain you were descended from a particular person back that far, you might not actually possess any of his genes.

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Humans have a high degree of genetic conservation, that is they share many genes with each other. Depending on what source you like, we're something like 98.5 to 99 percent genetically identical to chimps. That is unsurprising given our estimates that we have a common ancestor with chimps 15 million years ago, NOT to be confused with having descended from chimps. The greater the proportion of any particular regional group of humans you have, the more likely you are to have the same genes. The number 100 generations is arbitrary. Every gene has a number of forms, called alleles. Different gene loci have different number of possible alleles so loci with only a few alleles might be very conserved (read: they don't change) compared to your ancestors. Race, ethnicity, etc. are all very arbitrary concepts. The best you can do and remain scientific is to talk about regional, shared ancestry.

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Has anyone else participated in one of these studies?

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I assume youre talking about the The Genographic Project with National Geographic/IBM. My parents did it and just recieved their results a couple weeks ago. Cool stuff.

The Genographic Project

Thank you chrisnice, yes that is one of the studies I was referring to.
As to anyone else who is interested, it is a study of midochondrial DNA, which is only passed down through the maternal line and is never changed because it is not part of the genes invoved in the "mix" of mother and father. The only changes are slight mutations which take about 10,000(?) years to occur. It also involves the y chromozome which comes from the male.
For you religious zealots you will be happy to know that science has figured out that every human today is genetically linked to one man, and one of three women. (Does the arc come to mind?)
Furthermore the only way a gene is washed away, or wiped out, dissapears is if the person or persons who have the particular gene are not capable of procreation or if the products of their procreation are not viable. This is called natural selection.
As to the question of how far back. From the beginnings of the species know as homosapiens.

[xniNja]

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For you religious zealots you will be happy to know that science has figured out that every human today is genetically linked to one man, and one of three women. (Does the arc come to mind?)

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Just FYI, older religions talk about progenitors too.

Just FYI that is exactly why I used the blanket statement RELIGIOUS zealots, every myth known has had one paternal survivor.

[xniNja]

Understood, I just wanted to pre-empt this turning into a validation of Noah's Ark thread. (Which would be ugly.)

[BluffTHIS!]

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I've studied genetics a bit, certainly enough to address your question.

[ QUOTE ]
Thus even if you could be certain you were descended from a particular person back that far, you might not actually possess any of his genes.

[/ QUOTE ]

Humans have a high degree of genetic conservation, that is they share many genes with each other. Depending on what source you like, we're something like 98.5 to 99 percent genetically identical to chimps. That is unsurprising given our estimates that we have a common ancestor with chimps 15 million years ago, NOT to be confused with having descended from chimps. The greater the proportion of any particular regional group of humans you have, the more likely you are to have the same genes. The number 100 generations is arbitrary. Every gene has a number of forms, called alleles. Different gene loci have different number of possible alleles so loci with only a few alleles might be very conserved (read: they don't change) compared to your ancestors. Race, ethnicity, etc. are all very arbitrary concepts. The best you can do and remain scientific is to talk about regional, shared ancestry.

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I was not talking about overall genetic conservation, but about particular conservation. You get exactly equal numbers of genes from your parents. But of the genes you get from one, they are not necessarily an equal mix of those that parent received from your grandparents. This is of course why certain traits including facial likenesses show up in following generations. Thus when looking at desecendent generations, a certain anscestor's genetic contribution can be getting proportionately smaller than only halving it each generation would make it.

Actually I was careless in just saying 100 generations when it can easily be determined that after 16 generations there is a possibility that your descendants no longer possess your genetic traits provided that you are not duplicated in their family tree. We simply don't possess enough genes to inherit all the contributions of previous ancestors, and not very far back either. As I said, this has nothing to do with overall genetic conservation of the species in the evolutionary timeline.