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beskeptical
2005-May-19, 07:42 PM
Yahoo News today (http://story.news.yahoo.com/news?tmpl=story&cid=1539&e=1&u=/afp/20050519/sc_afp/indiasciencednatribe_050519172027) reported on genetic research on a tribe in India but included the following:
Mitochondrial DNA, which is passed maternally and found in every human cell, can be traced to a single female ancestor who lived about 150,000 to 200,000 years ago.

When the original story on the mitochondrial Eve was published I thought they had said it was a small group of perhaps a 1,000 individuals and not a single female. Sounds to me like the myth of a single ancestor as opposed to a small group of primates that became isolated and evolved into homosapiens will become the story unless someone objects loudly enough. They just shouldn't have used the term "Eve" as was one criticism leveled against the author of the original research.

Here's a search page (http://www.google.com/search?q=mitochondrial+eve&sourceid=mozilla-search&start=0&start=0&ie=utf-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-US:official) with lots of sources on the subject if anyone is interested.

Gullible Jones
2005-May-19, 08:06 PM
Gotta be bogus. You should be able to trace it back farther...

Van Rijn
2005-May-19, 08:35 PM
Yahoo News today (http://story.news.yahoo.com/news?tmpl=story&cid=1539&e=1&u=/afp/20050519/sc_afp/indiasciencednatribe_050519172027) reported on genetic research on a tribe in India but included the following:
Mitochondrial DNA, which is passed maternally and found in every human cell, can be traced to a single female ancestor who lived about 150,000 to 200,000 years ago.

When the original story on the mitochondrial Eve was published I thought they had said it was a small group of perhaps a 1,000 individuals and not a single female.

I remember when this first came out. I didn't look into it in detail, but I remember a lot of caveats and arguments. Obviously the "single ancestor" bit got a lot of play and was immediately dubbed "Eve." As I recall, the general conclusion was that it did imply there was a bottleneck at one time, but it didn't mean that there had to be only a single female ancester at one point. In a small population it can be more complicated than that, where there might be more than one mitachondrial line, and always more than one woman with them, but by chance over time a particular line might dominate, until one generation when there are no females born with an alternate sequence.

[edited for clarity]

lek
2005-May-19, 08:37 PM
Isnt mitochondrial Eve one person by definition?

Following the dna path to its origin reduces to one person inevitably... Whether or not it is possible to determine if it really reduces to one person or not is quite hard to determine really.
Only thing worth mentioning to make it more accurate is that if we could determine mito eve this year, she may not be the same person as it would be year from now.

01101001
2005-May-19, 08:42 PM
Gotta be bogus. You should be able to trace it back farther...
Of course. But only one such woman was most recent. I think we need a definition.

Wikipedia: Mitchochondrial Eve (http://en.wikipedia.org/wiki/Mitochondrial_Eve)


Although she was named after the Biblical Eve, mitochondrial Eve was not the sole living human female of her day. As many as 20,000 individuals of Eve's species may have lived at the same time as she. But only Eve produced an unbroken line of daughters that persists today. As a result, only Eve's mitochondria have descendants in the cells of living humans. Eve is the only female of her generation from whom all living people descend along their maternal lines.

Mitochondrial Eve was the most recent mitochondrial ancestor of all living humans, but, of course, her mother, maternal grandmother, and so on were also the maternal-line ancestors of all living humans.

The mitochondrial Eve for currently living humans was quite possibly not the same individual as the mitochondrial Eve for humans living thousands of years ago or thousands of years from now

Jim
2005-May-19, 08:46 PM
Gotta be bogus. You should be able to trace it back farther...

Nope, not bogus; mathematically required. And you can't go back further w/o finding some very well-preserved (as in readable DNA present) remains.

Check the TalkOrigins link in be's serach page for a fascinating - and fascinatingly simple - explanation.

That link also points out that we have an Adam in our past; but he lived several thousand years after our Eve.

(fixed a word)

Van Rijn
2005-May-19, 08:46 PM
Isnt mitochondrial Eve one person by definition?

Following the dna path to its origin reduces to one person inevitably...

I'd say no. There is no reason to assume that only one person at any time had this particular mitochondrial sequence. Also, this isn't about nuclear DNA, which is, for most purposes, far more significant. In any event, would you say that twins are the same person, even though they are the same genetically?

lek
2005-May-19, 09:41 PM
Isnt mitochondrial Eve one person by definition?

Following the dna path to its origin reduces to one person inevitably...

I'd say no. There is no reason to assume that only one person at any time had this particular mitochondrial sequence. Also, this isn't about nuclear DNA, which is, for most purposes, far more significant. In any event, would you say that twins are the same person, even though they are the same genetically?

You left out the rest of my post... which questions "how can we determine we have reached THE one person at the end of the chain" At least thats what i tried to say... Which in the example you gave would be the mother of those twins ;)

It's fair to question whether a single unique person with mitochondrial dna exists (meaning, have all the other paths died or not). But by definition anything we call "mito eve" is one person #-o

Sock puppet
2005-May-20, 02:17 PM
Isnt mitochondrial Eve one person by definition?

Following the dna path to its origin reduces to one person inevitably...

I'd say no. There is no reason to assume that only one person at any time had this particular mitochondrial sequence. Also, this isn't about nuclear DNA, which is, for most purposes, far more significant. In any event, would you say that twins are the same person, even though they are the same genetically?[bolding mine]

Well, any lineage of mitochondria must have an origin: one individual in which it first arises. Unless you are suggesting that an identical mutation occured in two members of the same population at the same time?

In fact, for almost every gene we posess(and by that I mean genes that every human has), all humanity is descended from the individual in which that gene originated. Exceptions would include cases where a retrovirus changed the DNA of those it infected and the changes were passed on.

Sam5
2005-May-20, 02:33 PM
They just shouldn't have used the term "Eve" as was one criticism leveled against the author of the original research.


What’s wrong with the classical name “Eve”? What would you call her? That name, and in fact this very concept, has been in Western and Middle-Eastern literature for the past 3,500 years, so why should we try to change it now?

Maksutov
2005-May-20, 02:51 PM
They just shouldn't have used the term "Eve" as was one criticism leveled against the author of the original research.


What’s wrong with the classical name “Eve”? What would you call her? That name, and in fact this very concept, has been in Western and Middle-Eastern literature for the past 3,500 years, so why should we try to change it now?
Simple. It's religiocentric.

Better names would be Lucy II, or Surya, or Maya, or maybe just the "common female ancestor". :D

ToSeek
2005-May-20, 02:54 PM
They just shouldn't have used the term "Eve" as was one criticism leveled against the author of the original research.


What’s wrong with the classical name “Eve”? What would you call her? That name, and in fact this very concept, has been in Western and Middle-Eastern literature for the past 3,500 years, so why should we try to change it now?

Not quite the same concept: Biblical Eve was the ancestress of all humans, ever. Mitochondrial Eve is the ancestress of all known living humans.

Sam5
2005-May-20, 06:20 PM
Mitochondrial Eve is the ancestress of all known living humans.


Hi, could you explain that in more detail please? The way you worded it, that makes it seem like all dead people are not related to her. So go into a little more detail about this biology theory. Thanks.

lek
2005-May-20, 07:11 PM
Mitochondrial Eve is the ancestress of all known living humans.


Hi, could you explain that in more detail please? The way you worded it, that makes it seem like all dead people are not related to her. So go into a little more detail about this biology theory. Thanks.

You got to the point there, mito-eve is the mother of all living people, but not the dead.

It's a case of piece of dna passed from mother to the kids, which is beeing traced. When all other strains but one have "died" only one remains, and the existence of the "eve" can be determined. The group "dead people" then contains all dead mitochondrial dna, and the one that is still beeing passed on.

01101001
2005-May-20, 07:15 PM
Mitochondrial Eve is the ancestress of all known living humans.

Hi, could you explain that in more detail please? The way you worded it, that makes it seem like all dead people are not related to her.

It's part of the definition. Some dead people were related to her. Some dead people were not. All living are.

ToSeek
2005-May-20, 07:27 PM
Mitochondrial Eve is the ancestress of all known living humans.


Hi, could you explain that in more detail please? The way you worded it, that makes it seem like all dead people are not related to her. So go into a little more detail about this biology theory. Thanks.

Talkorigins has a pretty good writeup (http://www.talkorigins.org/faqs/homs/mitoeve.html) on the rationale behind the concept. As it points out, Mitochondrial Eve is contextual. When she was alive, one of her distant ancestors was then Mitochondrial Eve. And of course there were plenty of other females alive at the time. However, their lines of female offspring died out. So there were populations of humans in the past who were not descended from this Mitochondrial Eve (but from some other).

To put it another way, I can extend my statement to say that Mitochondrial Eve is the ancestress of all known living humans and their matrilineal ancestors. However, there were populations in the past not descended from her. But the females in those populations did not give birth to females who gave birth to females who ... gave birth to people alive today.

I hope this helps. I'm not sure that I'm making things that much clearer.

lek
2005-May-20, 07:32 PM
I hope this helps. I'm not sure that I'm making things that much clearer.

Glad im not the only one :D That explanation look quite the same i was trying to make, but i lacked the words to make it as clear :oops:

edit 6: do i finally get the quoting right?, and typos? i shouldn tbe posting anything at this time of day obviously

SeanF
2005-May-20, 07:36 PM
Mitochondrial Eve is the ancestress of all known living humans.


Hi, could you explain that in more detail please? The way you worded it, that makes it seem like all dead people are not related to her. So go into a little more detail about this biology theory. Thanks.

Talkorigins has a pretty good writeup (http://www.talkorigins.org/faqs/homs/mitoeve.html) on the rationale behind the concept. As it points out, Mitochondrial Eve is contextual. When she was alive, one of her distant ancestors was then Mitochondrial Eve. And of course there were plenty of other females alive at the time. However, their lines of female offspring died out. So there were populations of humans in the past who were not descended from this Mitochondrial Eve (but from some other).

To put it another way, I can extend my statement to say that Mitochondrial Eve is the ancestress of all known living humans and their matrilineal ancestors. However, there were populations in the past not descended from her. But the females in those populations did not give birth to females who gave birth to females who ... gave birth to people alive today.

I hope this helps. I'm not sure that I'm making things that much clearer.
But that's all dependent on female offspring, correct? At some point in the past, we all had the same mother's mother's mother's mother's . . . mother. But my father's father's father's . . . father could be different than yours, even going back past this Mitochondrial Eve? In fact, my father's father's father's . . . mother would've been a different woman but a contemporary of Mitochondrial Eve?

Sam5
2005-May-20, 07:36 PM
Thanks for all the info! :D

Grey
2005-May-20, 07:59 PM
And as beskeptical pointed out, I'm not certain that the proof is really that strong that there was just a single mitochondrial ancestor. (Well, in principle I suppose there has to be one somewhere along the line, but there's no logical reason that it has to have been recent enough that such an ancestor would have been considered human).

Gillianren
2005-May-20, 08:12 PM
strangely enough, this is exactly the concept that the movie (predates the video game) Parasite Eve makes almost clear, before the mitochondria start killing people (or something; I was a little confused by that bit). what I don't know is if "Eve" appears in the original Japanese, or if it's an English translation.

Doodler
2005-May-20, 08:15 PM
Gotta call bogus here, how would the Eve ancestor change? If mito Eve was the ancestress of all currently living humans, how could an older "Eve" not be the ancestress of all currently living humans?

At some point, statistically, you've got to arrive back at one female and one male. What is implied there is a family tree that somehow "jumps tracks" and continues.

ToSeek
2005-May-20, 08:16 PM
At some point in the past, we all had the same mother's mother's mother's mother's . . . mother. But my father's father's father's . . . father could be different than yours, even going back past this Mitochondrial Eve? In fact, my father's father's father's . . . mother would've been a different woman but a contemporary of Mitochondrial Eve?

That's right.

There is a related concept referred to as "Y-chromosomal Adam", who is the father's father's father's ... father's father whom we all have in common. He is believed to have lived 60-90 thousand years ago and would not be a contemporary of Mitochondrial Eve.

ToSeek
2005-May-20, 08:19 PM
Gotta call bogus here, how would the Eve ancestor change? If mito Eve was the ancestress of all currently living humans, how could an older "Eve" not be the ancestress of all currently living humans?

At some point, statistically, you've got to arrive back at one female and one male. What is implied there is a family tree that somehow "jumps tracks" and continues.

Mitochondrial Eve can change forwards, not backwards. For example, if a plague killed everyone but your extended family, your great-grandmother could become the new Mitochondrial Eve.

Disinfo Agent
2005-May-20, 08:35 PM
Gotta call bogus here, how would the Eve ancestor change? If mito Eve was the ancestress of all currently living humans, how could an older "Eve" not be the ancestress of all currently living humans?

At some point, statistically, you've got to arrive back at one female and one male. What is implied there is a family tree that somehow "jumps tracks" and continues.
Read the essay at Talk Origins that beskeptical linked to above. It explains it all quite well.
Anyway, to cut a long story short, our mitochondrial Eve of today doesn't have to be the same as the mitochondrial Eve of two millennia from now, or the mitochondrial Eve of 6000 years ago.
It's a function of time, or, more precisely, of the living population.


At some point, statistically, you've got to arrive back at one female and one male.
No, no male. The concept of a "mitochondrial Eve" is only related to the part of our genome that is transmitted from each mother to her child.

beskeptical
2005-May-20, 10:17 PM
I think what bothers me here is folks are not as informed about mitochondrial DNA nor how a small group of primates would evolve into homosapiens, so they simplify the concept into a single ancestor line. But that isn't how evolutionary change necessarily always works. It depends on the structure and intermingling of the evolving group. It isn't like some great ape had a mutated offspring that was so different as to be the Eve.

Instead what you have are a small number of individuals who constitute a large enough group to be reproductively viable. The group may be interrelated enough to all have a common ancestor but the evolutionary changes haven't occurred at this point to give you a new species. The group can have just a few or perhaps a thousand members or more. The group splits off from other related groups and offspring only come from the isolated group.

For example in one place, bonobos live on one side of a large river and chimpanzees on the other. The two groups were isolated from each other many generations back and evolved on separate paths. They could still have a common ancestral line and related mitochondrial DNA. If one ancestor was their 'Eve' then that Eve wouldn't have been a bonobo or a chimpanzee.

So the group evolves, mutations accumulate but the group continues to intermingle. You don't have a single Eve.

The reason we are all one race now, despite being dispersed across the continents and despite having been isolated from each other for perhaps 60,000 years if you take groups like Australian Aboriginals, is that evolution is very slow. Australian Aboriginals have not been isolated long enough to have developed enough genetic changes to be a different race.

You don't get a single mutation and end up with homosapiens. You need a lot of mutations accumulating over time in a group that is sufficiently large as to be able to sustain reproduction, yet sufficiently isolated as to be changing in ways other groups of the same origin are not changing.

But reporters and persons not educated about the process of how a species evolves think you get one mutation and one Eve. Since that is the concept in their minds, they fail to remember the program or research on "mitochondrial Eve" said 'she' was a 'group', not an individual. And now as the story is repeated and built upon, it changes into "the one eve".