All humans are descended from just TWO people

[Farstar]

According to:

https://www.dailymail.co.uk/news/ar...iving-200-000-years-ago-scientists-claim.html

all humans descend from a couple. My probabilistic intuition fails here. It seems all our homo genes (in the billions of humans) descend from a given couple (even the genes of older homos, which are present in us only because they were present in that couple).

I can understand we descend from an "Eve", and from an "Adam", but it seems very unlikely that we descend from a single couple. But from the quoted article, this seems a very common event in Nature.

How can this be intuitively understood?

Note: my understanding of this article is as follows (I may be wrong, please correct me if necessary): at some point in time, there were X people on Earth. Of those X people, there were 2 that had some children. Out of the X - 2 remaining people, of course those X - 2 people had children, too. The conclusion of the article is that none of the descendants of those X - 2 left any descendant alive today. I find this very surprising. It is almost as if only two people on Earth existed at that time (plus other homo groups, maybe, far away, which became extinct later).

 

[Farstar]

No interest in this thread? I would be thrilled to get the input of the experts on this issue.

 

[paul333]

Well it may well be, that we only descend from a single ancestor/person/thing, a single cell Ameoba, which then split into two, if you can Adam and Eve it. ( ie, believe it ).

 

[bicicleur 2]

autosomal DNA goes back much further than uniparental
it's all explained in part 1 of David Reich's book 'Who we are and how we got there'

 

[Farstar]

autosomal DNA goes back much further than uniparental
it's all explained in part 1 of David Reich's book 'Who we are and how we got there'

Can you please expand a bit more?

 

[Megalophias]

The Daily Mail is not known for its accuracy, to put it mildly.

https://phys.org/news/2018-05-gene-survey-reveals-facets-evolution.html
https://phys.org/news/2018-05-special-humanity-tiny-dna-differences.html
http://www.pontecorboli.com/digital...05/22/why-should-mitochondria-define-species/

They are not indicating any change to the human maternal tree, their point is that even very numerous widespread species of animal also tend to have relatively recent maternal founders.

 

[LeBrok]

Maybe it was one tribe, not just two people. However, it doesn't matter much, because people were very related in small trib, they all had almost identical DNA.

 

[Farstar]

The news included in this thread, and the thread:

https://www.eupedia.com/forum/threa...n-were-wiped-out-by-Yamna-men-4-500-years-ago

seem to suggest a connection: some humans wipe out most, or all, the other humans they find, which are not their "kin".

Could this be a possible explanation of the fact stressed in this thread? That "life" tries to destroy the "similar-but-different" (maybe to avoid competition for food)?

 

[bigblob]

Absolutely not true:
https://www.sciencedaily.com/releases/2018/07/180711114544.htm
Humans originated from different groups of early humans in Africa. There were also archaic humans and Hominids living in Africa at the same time as modern humans.

 

[Wanderer]

Yes in terms of haplogroups. Theres only like one guy that has a more ancient divergent lineage.

 

[Ygorcs]

All they talk about is mitochondrial DNA. Is the study based on mitochondrial DNA alone? It's no news that human had a "Y-DNA Adam" and a "mitochondrial Eve", though they most probably did not live at the same time and in the same clan. But if that's it, no analysis of autosomal DNA, then it definitely DOES NOT mean that all humans are descended from just two people. All it means is that the only lineage that had at least 1 unbroken line of female descendants until the contemporary era dates back to that time. What's really weird is their conclusions about other animals (I can't vouch for their scientific reliability, I didn't see the study nor am I qualified to judge its methodology and statistics), in that they claim that other animal species also experienced that same pattern of tracing their mitochondrial DNA back to one single lineage around 100,000-200,000 years ago. I'm not sure if they're correct about that, though.

 

[markod]

All they talk about is mitochondrial DNA. Is the study based on mitochondrial DNA alone? It's no news that human had a "Y-DNA Adam" and a "mitochondrial Eve", though they most probably did not live at the same time and in the same clan. But if that's it, no analysis of autosomal DNA, then it definitely DOES NOT mean that all humans are descended from just two people. All it means is that the only lineage that had at least 1 unbroken line of female descendants until the contemporary era dates back to that time. What's really weird is their conclusions about other animals (I can't vouch for their scientific reliability, I didn't see the study nor am I qualified to judge its methodology and statistics), in that they claim that other animal species also experienced that same pattern of tracing their mitochondrial DNA back to one single lineage around 100,000-200,000 years ago. I'm not sure if they're correct about that, though.

This might be one of the reasons mtdna haplogroups went through founder effects across different species at around the same time:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3998521/