Peez

Yes and no.All humanity also came from them.That should not be a problem.I will try. It is not really a difficult concept once you have it, but it is a different enough idea that it can be tough to get it at first.

First, read the explanation I gave about 75% of the way down page 2 of the 14-year-old lands article in science journal thread. In that post, I started with 6 individuals, having 12 alleles (forms of a particular gene) at each of 3 loci (locations of particular genes on the chromosomes). After 10 generations, all individuals could trace their ancestry at locus A to one "Eve," but they could trace their ancestry at the other loci to some of Eve's contemporaries. After 21 generations, all individuals could trace their ancestry at locus A to one "Eve," and they could also trace their ancestry at locus B to one "Adam." Later still, after 28 generations, they can trace their ancestry at locus C to yet another individual.

So, when we talk about "mitochondrial Eve," we are talking about someone from whom we all inherited our mitochondrial DNA, but we inherited other DNA from that woman's contemporaries. This is due to the loss of mitochondria (and other DNA) by random chance (genetic drift). Far from being unlikely, this is pretty much certain given enough time. In fact, only one woman alive today will likely be the mitochondrial Eve for some generation far in the future.

Peez

Oolon Colluphid

And, presumably, there were also, in 'Eve' 's distant past, previous 'Eves' -- an mtEve^-1, and mtEve^-2, and so on...?

Say, if we discount the biblical story, does that make us Evedroppers?

Oolon

Peez

Yup. One could say that there is an "Eve" every generation.Ouch!





Peez

CX

Ummm...I'm lost again. Doesn't this mtDNA Eve inherit her mtDNA from our mtDNA Eve? Consequently won't that future generation have the same mtDNA Eve as we do? Also if all living humans inherited their mtDNA from the same individual won't all of them have descendants rather than just the one?

Or is genetic mutation playing some part in this. Which is to say that even though we all inherited our mtDNA from the same ancestor not all of our mtDNA is exactly the same. If that's the case then what does it actually mean to say we inherited from one ancestor and how do we know?

theyeti

mtDNA Eve is defined as the most recent female from whom everyone's mtDNA comes. Eve had a mother (and a maternal grandmother), from whom all of our mtDNA came also. But we define Eve as the most recent ancestor on whom everyone's strict maternal lines converge. There may well be a female alive today who will be mitochondrial Eve for future generations (it won't be my mom, because she only had sons). Likewise, there was a mitochondrial Eve back in the day when our current mitochondrial Eve was living. Personally, I think it's unlikely that mitochondrial Eve will be shifted to more recent times without a major die-off, but maybe Rufus or Peez can chime in on that.

I posted some comments on the other thread trying to explain the concept (assuming I got it right).

theyeti

WinAce

Congratulations, you've won the "Worst Pun 2003" award. The check is in the mail

Roller

Thanks Peez!

Oolon Colluphid

Nah, the cheque's yours. I said it; you overheard it...

mark24

Yes, all it does is increase homozygosity.

In effect you are introducing lethal/deleterious alles in the homozygous form, which are selected against. These alleles are ultimately removed from the genome in this way.

Mark