I believe that the theory they're supposed to be debunking is not that the old (>300,000 yrs) sapiens population descended from a single regional population. The theory is that by 300k ybp there was a divverse sapiens population in and near Africa. They had a wider range of physical appearance than modern humans. Our ancestors descended from a sub-population of archaic sapiens (before mixing with other homo species).
The theory explains why we're so much more homogeneous than very old sapiens who still sometimes exhibited "primitive" (isn't this a truism?) skull shapes and such. We went through a bottleneck at some point.
IE, many flavours of sapiens existed. We descend from one of them. The Morocco & Levant sapiens have no descendants.
every article or paper on this topic in the last 10 years talked about a complicated network of genetic branches instead of a simple linear tree
>a complicated network of genetic branches...
kind of implies a tree.
I haven't read the other papers, but, at it's root, the paper that is the subject of this posting seems to imply that the root species came much, much earlier than we typically believe. I'd need more access to the genetic data they are basing that conclusion on to know if they are right? But it sounds right. Why could sapiens not have risen in Africa millions of years earlier? (At the same time, we have to be careful. Sounding right is not how we should be evaluating scientific theories.)
> >a complicated network of genetic branches...
> kind of implies a tree.
Not quite. The implication is that some separate branches that developed distinct (but not incompatible) differences over time due to geographical or social separation later merged into other branches, meaning that there isn't a simple linear sequence from every point in the tree back to the one root.
Now let's convince linguists that Semitic and PIE languages are related and we have won!
I'm not getting at the science or it's practitioners, they can't just make up complex changes without evidence, but let's be honest that any such seemingly static periods of history due to limited evidence are probably just placeholder theories for whatever was actually happening.
Early historians used to call them dark because of just such "limited evidence". Little surviving records, compared to the periods before/after.
But these "periods of silence" may have given us something less tangible but even more lasting than literature and architecture. The fabric of societies was rewoven, new modes of thinking and organization emerged from the chaos. People may not have been into books and stone, but they were certainly not idle!
The inhales and exhales at the scale of humanity are sometimes hard to appreciate, or even tell apart, from our individual level.
This was a very controversial result, in part because the length of human history was so young (much less than the 1 million years that some fossils suggested), and because the origin was placed in Africa. Shortly after this, I heard Wilson discuss the controversy, and he remarked that he was surprised that there was so much disagreement about the idea that a set of genes in a population could be attributed to a single individual. He pointed out that this was well understood by population biologists in the early 20th century; basically, for any population of individuals at some time in the past, after a long enough time, the descendants of that population will have genes that can be traced back to one individual -- that one individual whose children had children who had children ... Though well established in 1987 (and decades earlier), but it was still argued about (and apparently still is).
Mitochondrial DNA can be traced back to an individual Africa (mitochondrial eve), less than 300,000 years ago.
This part doesn't make sense. The controversy must have been a misunderstanding. 'mt-MRCA' is a moving target. It is the most recent common ancestor (MRCA) of the currently living population. The mt-MRCA for the population earlier in time would be older than the current mt-MRCA. Similarly for Y-MRCA.
In the early aughts, my TA in University was writing a similar paper for his doctoral degree. All of the professors in the department said it was good enough to be a PhD paper.
His premise was there were several divergent populations not only in Africa, but in Nordic regions and Eastern Europe from where we evolved from.
It's cool to see this shift in the dominant paradigm is finally starting to shift, some 20 years after my TA (and presumably many others) proposed it.
To me it is fascinating to imagine what this species was like with their larger brains, but smaller frontal lobes, which are believed to have been more-focused on their senses and athleticism.
Once you believe there is a strong causation between skull shape and intelligence, the racist conclusions write themselves.
I assume good faith on the part of the GP, though.
I didn't have any idea anyone would interpret this as racist, wtf?
The discussion on skull evolution I reference here is also mentioned in the OP. How can I be accused of racism and not the OP? That isn't consistent.
Don't get hostile or defensive over a misunderstanding, please.
Denisovan DNA for instance, of which there is no sign in any African and very few European people...
My intuition is that something extremely similar happened for Neanderthals in Europe and Denisovans in Asia.
After speciating, Denisovans and Neanderthals migrated at least within Eurasia, and those populations intermixed.
At least as early as that was happening, Homo sapiens started migrating out of Africa, and intermixed with the Homo genus populations they encountered. At some later point, distinctly Neanderthal, Denisovan, and Neanderthal/Denisovan populations apparently died off.