by gauravsc on 10/8/20, 9:48 PM with 95 comments
by dfischer on 10/8/20, 10:52 PM
> Today, H. sapiens doesn’t have the possibility of quickly grabbing a load of diversity by mating with another group: For perhaps the first time in our history, we’re the only humans on the planet. It’s another reason to miss our extinct cousins, says population geneticist Carina Schlebusch of Uppsala University. “To have such a large densely spread species with … so little genetic diversity … is a dangerous situation,” she says.
by adenozine on 10/8/20, 10:47 PM
I know it's macabre, but I think about human migratory routines and when different groups clashed back when life was so primitive and brutish, they're must've been those tendencies to rape and sexually conquer the opposition.
Surely that is reflected in the genetic ledger of time. What a crazy insight. Genetics is such an interesting field. It's bonkers there's just strings of data that we can read the past through.
by jimktrains2 on 10/8/20, 10:53 PM
I think it's most interesting to think of how fluid what we mean by species really is. We've always known it was fluid, but I think many people never really consider that when thinking about ourselves.
by tzs on 10/9/20, 3:06 AM
In the case of Neanderthals, isn't that "all" people rather than "many" people?
Neanderthals are believed to have gone extinct 40000 years ago.
But there was an article here the other day about the genetic isopoint [1], which is the most recent time when every human alive then was either an ancestor of every human currently alive or had no descendants that are currently alive.
Most researchers put the genetic isopoint somewhere between about 4000-15000 years ago.
If both of these are true (or even if not, as long as the genetic isopoint is after Neanderthal extinction), then all my ancestors that descended from Neanderthals and were alive at the genetic isopoint are also your ancestors, and so you are also descended from Neanderthals through them.
There seems to be a lot more uncertainty about when the Denisovans went extinct. It seems likely that they were probably also all gone by the isopoint and so "all" rather than "many" probably goes for them too.
by sradman on 10/9/20, 9:41 AM
> ...which involves only three expansions of humans from Africa into Eurasia: an expansion of early Homo at about 1.9 Ma ago, an expansion of neandersovans at about 700 ka ago, and an expansion of modern humans at about 50 ka ago.
The “early Homo” or “superarchaics” are H. erectus and their DNA contribution is inferred since no sequences have yet been extracted. “Neandersovans” is the common ancestor of European Neanderthals and Asian Denisovans.
Interbreeding occurred in Eurasia after the second and third expansion.