Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: wizardof1977 on 20/02/2019 10:47:21

Title: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: wizardof1977 on 20/02/2019 10:47:21
Hi,
Apologies if this was discussed before but I keep getting an article from different science publications talking about a Mitochondrial Eve that lived 200k years ago and that this is a proof of the existence of Adam and Eve.
Can those in the know explain to me how all 7 billion of us have descended from one woman?


Cheers!
Wiz
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: Halc on 20/02/2019 12:08:53
Hi,
Apologies if this was discussed before but I keep getting an article from different science publications talking about a Mitochondrial Eve that lived 200k years ago and that this is a proof of the existence of Adam and Eve.
Can those in the know explain to me how all 7 billion of us have descended from one woman?
The biological Adam is the last person who is a common ancestor of all humanity.  This person could be male or female, and lived more recently than the biological Eve. The biological Eve is the last person who is a direct female descendant (mother's mother...) of all people on Earth.
This does not mean that there were no other women or that she didn't have a mother.  It means that she had at least two daughters, and there is at least one woman on Earth that is directly (female line) descended from each of those daughters.  If the last of one of either of these groups of people die, then the other daughter (or one of her descendants) becomes the new biological Eve.
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: alancalverd on 20/02/2019 12:46:40
Quite simply, as far as we know every homo sapiens carries an identical chunk of mitochondrial DNA that hasn't evolved, the species appears to have originated in east Africa, and mitochondrial DNA is inherited in the female line. We look different as a result of spontaneous evolution and possible interbreeding with extinct relatives like neanderthalensis, but this chunk is remarkably consistent and dominant.

 No big deal. I live near the grave of Godolphin Arab, from which practically every modern racehorse is descended, though the male DNA inheritance is less consistent.
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: Halc on 20/02/2019 12:48:46
and that this is a proof of the existence of Adam and Eve
That they chose to use these symbolic names is by no means evidence (let alone proof) that there was a single pair of people in all existence at one time.  It can be shown that such a being must exist given the way we reproduce.  Take any group of life forms, and there exists a biological Eve for that group.  Take just me and my dog for instance.  Keep going back to our mother's mother further and further back, and eventually the two of us will find a common female ancestor that is neither primate nor canine.  That's the biological Even of the two of us.  There is one for all mammals, and even between myself and a tulip.
Quote
Can those in the know explain to me how all 7 billion of us have descended from one woman?
It is easy to demonstrate.  Suppose it were otherwise, that there was no such common ancestor.  It would require that abiogenesis (an incredibly unlikely event) occurred multiple times on Earth, and that some humans are descended from one of them, and other ones separately evolved to the same form (an even more unlikely event), from the other primitive life.
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: Halc on 20/02/2019 12:54:03
Quite simply, as far as we know every homo sapiens carries an identical chunk of mitochondrial DNA that hasn't evolved,
It has very much evolved.  The differences are how they can track from which line a given person belongs.  If they hadn't evolved at all, there would be no way to perform this tracking, and they would not know the approximate age of the biological Eve.
It just doesn't evolve the way normal DNA does, with contributions from both parents.  Mitochondrial DNA reproduces the old sexless way and is passed only through the maternal line.
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: wizardof1977 on 20/02/2019 13:21:58
Thank you all for these replies
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: alancalverd on 20/02/2019 14:45:50
It has very much evolved. 
Surely there must be some characteristic bit that hasn't changed, otherwise we wouldn't all have it in common?
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: Halc on 20/02/2019 15:11:47
Surely there must be some characteristic bit that hasn't changed, otherwise we wouldn't all have it in common?
Sure, but it is the differences (mutations) that allow the tracking, not the vast majority that hasn't changed in 200 M years.

Heck, I share a lot of DNA with the dandelion in my yard.  Not sure how much mitochondrial genes are shared.  Maybe even more...
Title: Re: Mitochondrial Eve - Does it mean Biblical adam and eve are real?
Post by: evan_au on 20/02/2019 20:43:40
Quote from: alancalverd
Surely there must be some characteristic bit that hasn't changed,
The unchanged bit is that it occurs in human mitochondria.
All parts of mitochondrial DNA can suffer mutations (even some mutations that are eventually lethal - but these are less likely to be passed on to the next generation).

Mitochondrial DNA is easier to sequence than nuclear DNA, since each cell has many copies.

See: https://en.wikipedia.org/wiki/Human_mitochondrial_genetics

A similar inheritance situation occurs for the nuclear Y chromosome, which men inherit only from their father. This allows tracing the line of male dependence.
See: https://en.wikipedia.org/wiki/Human_Y-chromosome_DNA_haplogroup