h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

scientists now believe that all of mankind is descended from 1 (or not many more than 1) women. we call this women, the "Mitochondrial Eve". what evidence is there for a "Mitochondrial Eve". Does this "Mitochondrial Eve" refers to eve in the garden of eden ?

Hi LF

I see that you are new to h2, so welcome aboard

Your questions are interesting. Do you have a weblink that might give us a bit more background on the topic?

I'm curious as to why she is being referred to as _mitochondrial_ eve. What part does the mitochondria play in the theory?


kea.

You can trace mitochrondria down the maternal line, the idea being you could trace them down to eve. Whether that is the biblical eve has become the name for the idea of teh first woman.

a simple explanation is here
http://dsc.discovery.com/convergence/realeve/feature/feature.html

It is not as I understand it that we are all descended from this one woman but that we all share her as an ancestor, you may say this is just semantics but the point I'm making is that by saying we are descended from someone has the connotation that at some point in history there was only she her to be descended from.

There is also a genetic "Adam" though he is about 50,000 years younger than "Eve".

That said the entire human race can be traced back to 73 individuals, so we are all a little inbred.

Inbreeding may occur in a closed population, but in a population which is young and experiencing its first mutations its quite the opposite. Else how come certain creatures brought back from the verge of extinction go on to form viable populations?

Perhaps it's because it is late, that I'm not quite following your point...

hey guys... i think you missed an important concept here. the mitochondrial eve HAS to exist, as long as you "believe" in evolution. all organisms are related if you go back far enough. in this case, if you look at the family tree of all living humans and trace back far enough, you have to reach some point where you find our oldest common relative -- the question is where and when.

it's called "mitochondrial eve" because mitochondria (organelles inside your cells) have their own DNA, and you inherit this DNA from your mother only.

to clarify further...

mitochondrial eve was not the first woman, or a special woman, she's just the oldest common female ancestor of all living people. as people die, the person who theoretically represents mitochondrial eve will change.

Yep I studied this back at Uni, I know exactly what it is. I also write a science column so I am up-to-date with scientific concepts and discoveries. Theres no way you could not know about all this when you read New Scientist every week.

Mitochondrial Eve doesn't have to be human though... There is no reason why all humans absolutely have to share a an individual in their Ancestry

I'm claiming we're all descended from giant lizards from Sirius!

Yes there is.

Go on then. Why should all humans share the same individual human ancestor?

*waits for the punchline*

This is not a new theory, in the last ice age homo sapien and homo erectus (a less sophisticated form of homo sapien) were forced to live together, in eurpoe at least, they interbred and as a result homo sapien was able to survive this period of hardship. Many of the people in eurpoe died and as a result all of the surviving people are the direct ancestors of these few people and so if you go back far enough you will find a disaster that has decimated the precourcers of the human race to the point that there was only a single breeding female.

I think mitochondrial eve is the only common *female* ancestor of all women, because, as has been pointed out, mitochondria are passed through the mother but not the father.

Consider an analogy - surnames. Surnames are passed from father to son, but not daughters (who in this scenario ALWAYS get married and never pass on their own surname). So if I have 4 children, 2 of which are female, my surname is only passed onto half of my descendants. My daughters carry half my genes, but not my surname. Taking this further logically, half my descendants lose my surname every generation because only half of them are male. In the same way, after thousands of generations most women's mitochondria are lost, and eventually only one (or a few) are left. Women whose mitochondria are no longer extant may still have thousands or millions of descendants.


Prince of shadow, as far as I'm aware, the genetic evidence points overwhelmingly to a recent African origin for ALL of humanity. Early homo sapiens contemporaries were homo neanderthalis, generally considered to be a separate species (though there is a highly charged paleoanthropological battle going on between the opposing camps).

I don't see, such calamities aside, why all humans would have to share a common human ancestor, the fact that the Adam and the Eve lived 50,000 years apart, adds to my point, a population can evolve towards being human without inheiriting the necessary mutations from one single individual.

I am aware of the thoeries relating to all human life developing in Africa. But humanity migrated out into the rest of the world twice once as homo erectus and then again as homo sapien. This allowed homo erectus to survive long enough to breed with homo sapien.