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Comment by lunaru | Hacker News Reader

Honest question: Let X be the single common-father. What was X-1? That is, what was X's dad? Not human?

The article uses somewhat confusing language, but I think this is about the most recent common patrilinear ancestor; now older than what was assumed before. So, the father of a patrilinear MRCA would obviously also have been a common ancestor, but not the most recent one.

"Patrilinear" means that all male humans can trace a path to the ancestral individual that contains only males. Whether the same individual is also the ancestor of all living females cannot be known based on the Y-chromosomal evidence.

If we allow paths that contain both males and females, the MRCA of all living humans may have lived remarkably close to the present time - circa 3000 BCE, based on many estimates.

http://en.wikipedia.org/wiki/Most_recent_common_ancestor

Can 3000 years be even close to being true? What about, for example, aboriginals in Australia. Is it not believed that they were an isolated population for 40,000-50,000 years?

Wikipedia: "An explanation of this recent MRCA date is that, while humanity's MRCA was indeed a Paleolithic individual up to early modern times, the European explorers of the 16th and 17th centuries would have fathered enough offspring so that some "mainland" ancestry by today pervades remote habitats. The possibility remains that an isolated population with no recent "mainland" admixture persists somewhere, which would immediately push back the date of humanity's MRCA by many millennia. While simulations help estimate probabilities, the question can be resolved only by genetically testing every living human individual."

It's possible. For example, if all living Australian aboriginals were to have a European explorer as an ancestor.

(I'm not trying to suggest that this is the case, I'm pointing out how they could have jumped the tree, so to speak)

This has little to do with what is "human" and what isn't. "Father of all humankind" is just a figure of speech, not any scientific assertion about this character.

Ignore species distinctions for a moment. Just tihnk about all the organisms that begat the people alive on earth today (that is, all their parents), and then the parents of those, and so on back. Eventually, you will find a organism that begat every person alive today in a direct line. The question is how far back in history you have to go to find such a person/thing. Note that there will be many such people (and this person was by no means the only person alive at the time, or anything like that -- just one of many, who had several children, who all had several children, who eventually interbred with all other humans). In fact, that person's parents are also the common parents of all mankind, and so on, so this isn't going to be a unique or special distinction; we're just curious about the most recent.

I'm not an expert, but I would assume X would have a genetic mutation that branches off of the lineage of X-1 and continues on, now technically being "human". Obviously this isn't a single person, but rather an estimate for the time period where this branching occurred.

Or something like that. How close am I?

The human race is a hodgepodge of various creatures in the genus Homo. Making distinct seperations like this is nearly impossible to stipulate.

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