Mitochondrial Eve | Hacker News Reader

Mitochondrial Eve

en.wikipedia.org

25 pointsthunderbong6 comments

Fun facts for today's lucky 10,000:

It's a useful mnemonic but also a misleading one when compared to the Biblical account:

- "Mitochondrial Eve" was not the only woman alive at the time, just the only one who still has surviving descendants

- She did not live at the same time as Y-chromosomal Adam, unless by sheer coincidence. They likely never met even if they were the same age.

- Both of these are titles, not people. As family lines die out, they both forward in time to new individuals. 1,000 years ago we probably had a different Adam and Eve who lived earlier in time.

- There's a book "Seven Daughters of Eve" which follows the splitting of haploid groups from Mitochondrial Eve, but you can pick any arbitrary number. They were not literally her daughters, and you could just as easily split further to get 8 or 9 or 100 of them.

It's neat stuff, but it's more "This is how math works" than "This is a historical account of a real-life woman and man who never met but their favorite color was blue."

https://xkcd.com/1545/ One day I too will either be the ancestor of all living humans, or none of them! I guess I'd be Y-chromosomal Eve lol

> - "Mitochondrial Eve" was not the only woman alive at the time, just the only one who still has surviving descendants

The only one who still have surviving descendants /in a purely maternal line/. I guess most of the women of her time have descendants today, but at some (many, in most cases) point in the descendance passes through a male.

Yes. If we consider genealogical rather than genetic inheritance, then incredibly you only have to go back 5,000 years or so to find a common ancestor.

https://johnhawks.net/weblog/when-did-humankinds-last-common...

To me it's not even that incredible, after some thinking. The number of descendants (and ascendants) of a single person grows exponentially with time. Assuming that a certain closed population remains constant, it means that most of the 2^n descendants of a single person after n generations are actually a much smaller group of people counted many times each (i.e., through different lineages), for n large enough (but not even too much). So there is some "pressure" for essentially everybody in the closed population to eventually become descendant of a given person after a number of generations roughly comparable to the logarithm of the population size. Estimating that a generation take 25 years, 5000 years means 200 generations. 1.12^200 ~= 7 billion, so a logarithm base of 1.12 is already around enough to justify the common ancestor age.

The world population is not constant, of course, and it doesn't behave according to the assumptions I made implicitly, but the order of magnitude makes sense. A single person moving from a people to another is enough to unify the two lineages.

Just don't go to an opera where she's the leading lady.[0]

[0] https://en.wikipedia.org/wiki/Parasite_Eve_(video_game)

Y-chromosomal Adam, aka Y-MRCA, must be due a spoof Village People number ...

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