Help needed on Mitochondrial Eve

[Research1]

I need help understanding about Mitochondrial Eve, so here are my questions, or what i am stuck/confused about below.

* Mitochondrial Eve apparently was the woman from whom all living humans today descend ??? However i then research this (i.e on wikipedia) and it says:

''One of the misconceptions of mitochondrial Eve is that since all women alive today descended in a direct unbroken female line from her that she was the only woman alive at the time. However nuclear DNA studies indicate that the size of the ancient human population never dropped below some tens of thousands; there were many other women around at Eve's time with descendants alive today, but somewhere in all their lines of descent there is at least one generation with no female offspring (and men do not pass on their mothers' mitochondrial DNA to their children). By contrast, Eve's lines of descent to each person alive today includes at least one line of descent to each person which is purely matrilineal''

I don't understand what this is saying. First we all come from a single eve (woman) then it says there were thousands of woman around at the same time as the mitochondrial eve who people descend from.

* The date for michondrial eve, figures range from 200,000 - 100,000 years old??? Then i see there are Young earth creationists saying a scientist discovered it was only 6, 500 years ago i.e to quote:

''According to one review of the data, these recent results would mean that mitochondrial Eve ‘lived about 6500 years ago—a figure clearly incompatible with current theories on human origins''

* Lastly how did they determine mitochondrial Eve? Going to a science website said they tested 147 people and that pointed to a common origin for all of them. However there are over 6 billion people on earth ??? 147 seems such a low figure. Is this accurate or have wider tests been done on this?

 

[DutchGirly]

For your first question: it means exactly what it says. There were a lot of women around when mitochondrial eve lived, but all the currently living people are descended from 1 woman via the maternal line.

Let's give an easy example with just 3 generations. The first generation consists of Adam, Abe, Anna, and Agnes. Adam makes 2 kids with Anna (say.. Bob and Beatrice), and Abe makes 2 kids with Agnes (Bill and Brenda).

Then disaster strikes, and Brenda dies during her childhood. Luckily for humankind, Beatrice is pretty fertile and gets 4 kids with Bill (Clarence, Clarice, Chris, Christina..)

Now, all the C kids have the following lineages:

C -> Beatrice -> Adam
C -> Beatrice -> Anna
C -> Bill -> Abe
C -> Bill -> Agnes

Agnes has grandchildren.. but all of those grandchildren are through her son Bill. And since men don't pass on their mitochondrial DNA, none of the C kids has Agnes' mitochondrial DNA.

Instead, all the C kids got their mitochondrial DNA from Beatrice, who in turn got it from Anna.

So through the female line, all C kids descended from just 1 woman (Anna), even though Anna wasn't the only woman alive. It's the same for mitochondrial eve, only on a larger scale.

 

[Research1]

Thanks for the reply, but i still don't get it.

It says everyone on earth descended from one woman, then at the same time claims other woman existed and that from these other woman there are modern descendants - so quite obviously that means not everyone descends from one woman.

I don't believe in monogenism anyway, i'm just researching it and trying to understand it.

 

[DutchGirly]

Thanks for the reply, but i still don't get it.

It says everyone on earth descended from one woman,

descended from one woman through the female line. Look at my example again. Agnes has grandchildren, but she doesn't have any grandchildren through the female line. You can't say "C is the daughter of ... who is the daughter of Agnes".

 

[sfs]

Thanks for the reply, but i still don't get it.

It says everyone on earth descended from one woman, then at the same time claims other woman existed and that from these other woman there are modern descendants - so quite obviously that means not everyone descends from one woman.

You're descended from more than one woman in each generation (except for the last). You have two grandmothers, 4 great-grandmothers, 8 great-great-grandmothers, etc. You only get you mitochondrial DNA from one of those: your mother's mother's mother's . . . mother. You're still descended from the others, though.

Mitochondrial Eve is the most recent woman from whom all current people inherit their mitochondrial DNA. In other words, she's the most recent ancestor of everyone from mother to daughter to daughter . . ., with no intervening sons. We're also descended from other women in her generation, but not by purely female descent. We've got other grandmothers in that generation.

 

[Research1]

Sorry i'm a bit slow on science stuff, but i understand it now. Thanks.

Is there any way though that this could not be true?

For example as i pointed out only 147 people were tested for the michondrial eve. I know they took these people from all over the globe but i don't think its conclusive. The figure seems far too low to be reasonable.

 

[sfs]

Is there any way though that this could not be true?

For example as i pointed out only 147 people were tested for the michondrial eve. I know they took these people from all over the globe but i don't think its conclusive. The figure seems far too low to be reasonable.

Until you look at every single family, you can not tell with absolute confidence that you haven't missed an old mitochondrial lineage, but the chances you have drop pretty quickly as the number of samples mounts. This is because the odds of an old lineage hanging around at low frequency is small: low frequency genetic variants tend to disappear because of random genetic drift.

In any case, far more mitochondria have been analyzed than in that single study. I believe there are now over 8000 complete human mitochondrial genomes that have been sequenced, and many more that have been examined in part. So the odds of something rare and old being out there are very small.

Note that even if there were such a lineage, it would just move mitochondrial Eve back in time, to an earlier generation.

 

[Itinerant Lurker]

National Geographics Genographic Project is a good place to start learning more about this issue.




Lurker

 

[lucaspa]

I need help understanding about Mitochondrial Eve, so here are my questions, or what i am stuck/confused about below.

* Mitochondrial Eve apparently was the woman from whom all living humans today descend ??? However i then research this (i.e on wikipedia) and it says:

''One of the misconceptions of mitochondrial Eve is that since all women alive today descended in a direct unbroken female line from her that she was the only woman alive at the time. However nuclear DNA studies indicate that the size of the ancient human population never dropped below some tens of thousands; there were many other women around at Eve's time with descendants alive today, but somewhere in all their lines of descent there is at least one generation with no female offspring (and men do not pass on their mothers' mitochondrial DNA to their children). By contrast, Eve's lines of descent to each person alive today includes at least one line of descent to each person which is purely matrilineal''

I don't understand what this is saying.

Let me try to illustrate this with the Y-chromosome and my family, because the same argument applies to Y-chromosome Adam.

My grandfather had a son and a daughter. Only the son, of course, got his y-chromosome. My father (the son) had a son and a daughter. I (the son) had 2 daughters. Therefore, no men in the future will get their Y-chromosome from my grandfather.

Do you get it? There were many women around when mitochondrial Eve lived. Either they had sons (and thus no mitochondria from the women), or their daughters or granddaughters all had sons. Only that one woman alive then had daughters who had daughters who had daughters who had daughters .... down to today.

* The date for michondrial eve, figures range from 200,000 - 100,000 years old??? Then i see there are Young earth creationists saying a scientist discovered it was only 6, 500 years ago i.e to quote:

The YEC is giving false witness.

 

[Ar Cosc]

It took me ages to get my head around it as well. I was thinking "If mDNA was only transferred from mother to daughter, then I don't have it, so my kids won't have it."

Completely forgot that I'll be needing a woman (with mDNA) to make any kids!

 

[lucaspa]

It took me ages to get my head around it as well. I was thinking "If mDNA was only transferred from mother to daughter, then I don't have it, so my kids won't have it."

So if your mother had only boys, then her mtDNA is going to be eliminated from the human species.

Your children are going to get their mom's mtDNA, but not your mom's.

 

[Ar Cosc]

So if your mother had only boys, then her mtDNA is going to be eliminated from the human species.

Your children are going to get their mom's mtDNA, but not your mom's.

I know, it's actually incredible simple, but you wouldn't believe how long it took me to work it out!

 

[Jazer]

It took me ages to get my head around it as well. I was thinking "If mDNA was only transferred from mother to daughter, then I don't have it, so my kids won't have it."

Completely forgot that I'll be needing a woman (with mDNA) to make any kids!

God was able to make Eve from Adams rib. So he was able to pass on the MtDNA that he science tell us he got from his mother.

 

[Exiledoomsayer]

God was able to make Eve from Adams rib. So he was able to pass on the MtDNA that he science tell us he got from his mother.

The only logical conclusion: God is a woman.

 

[Jazer]

* The date for michondrial eve, figures range from 200,000 - 100,000 years old??? Then i see there are Young earth creationists saying a scientist discovered it was only 6, 500 years ago i.e to quote:

The Eve in the Bible was a real person. She was the mother of the Hebrew nation. Now science tells us that in Europe alone there were 7 Eves. The Bible is a History of the Jewish people. The geneologys in the Bible are for the Hebrew people. Bible Eve and Science Eve are two different people according to Science. Bryan Sykes wrote a book that explains all of this.

 

[Steve Petersen]

On the other side of the coin, there is one chromosome that men only pass to their sons, nu?

 

[Michael]

I don't understand what this is saying. First we all come from a single eve (woman) then it says there were thousands of woman around at the same time as the mitochondrial eve who people descend from.

I have a theory about that. My theory is that Eve was exceptionally "hot" and passed on her exceptional good looks to her daughters. That cuteness became a highly desirable quality in women, and therefore her genetics won out over time. Now all women have some of her hot DNA, some more than others.

That my theory anyway, and I'm sticking to it.

FYI, forget YEC, it's been falsified a thousand times in a thousand different ways.

 

[Lion Hearted Man]

On the other side of the coin, there is one chromosome that men only pass to their sons, nu?

Gender is pretty ambiguous at certain stages of development. Men have all the genes to become ladies...the Y chromosome is mostly a glorified switch to turn on the testes genes.

 

[sfs]

On the other side of the coin, there is one chromosome that men only pass to their sons, nu?

Yes, the Y chromosome.

 

[Incariol]

On the other side of the coin, there is one chromosome that men only pass to their sons, nu?

Yes, the Y chromosome.

No, you get 23 chromosomes from each parent. It is just that the 23rd chromosome, which is sex determining, can be either an XX pairing, or an XY pairing, and the Y can only come from the father.

Or maybe you meant that, but whatever. It looked like you were saying men only pass on the Y chromosome.