Interesting in the limelight of pandemics in regards to the closing paragraph:
> 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.
Even as the single human species we used to be spread into isolated groups, that's why different populations have specificities (e.g. skin colour, but also other adaptations).
Now that we have such a huge and interconnected population diversity will fade and adaptation will slow.
This sentence doesn't make any sense: "H. sapiens doesn’t have the possibility of quickly grabbing a load of diversity by mating with another group".
It would make sense if she specifically referred to Homo sapiens sapiens, but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them.
Also Homo sapiens sapiens have plenty of genetic diversity. Even just the number of easily observable environmental adaptions present in populations are countless (Sherpa, Bajau people, etc.)
As for COVID-19, most people are more-or-less unaffected by it. Our genetic diversity is working as intended.
Man, I've always actually kinda wondered about this.
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.
I encourage you to explore the early history of the pre-Roman Empire peoples. These were largely mythologies that the romans retroactively constructed for themselves (i.e. they had the opportunity to omit the raping and kidnapping in retellings, but chose not to).
It’s full of “and then tribe X invaded and the land of Y, took their women and enslaved their men”. Back and forth for centuries. This behavior was cyclical, inevitable, and universal, until violence was monopolized and institutionalized.
We’ve come a long way, I guess. Still have work to do.
There was inevitably conflict, but I'm skeptical of the "tendencies to rape and sexually conquer the opposition" framing. AFAIK there isn't much evidence for large amounts of inter-group violence. A paper like https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23751 lays out a contra case that the absence of evidence isn't evidence of absence--but I think it is a reason to be cautious about what we project back on those populations.
It's a running joke in Dr who, where as humanity spreads into the starts there eventually ceases to be any pure humans (and many other alien species) because humans will mate with anything.
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.
Dr. Who is wrong. We could not mate with anything amongst the stars. Even if aliens exist they would be radically different. You might as well as bone your VCR.
The act of separation would create new species. Not our drive to bone.
> The story of human evolution is full of ancient trysts. Genes from fossils have shown that the ancestors of many living people mated with Neanderthals and with Denisovans, a mysterious group of extinct humans who lived in Asia
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.
I'm not sure it's 'all'. Khoi-San peoples were pretty well isolated reproductively until recently and diverged before the Neanderthal introgression dates that I'm aware of. They're pretty much the reason the mt-MRCA and Y-MRCA dates are so old.
The paper Neanderthal-Denisovan ancestors interbred with a distantly related hominin [1] suggests a simple model of hominid population movement
> ...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.
dfischer|5 years ago
> 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.
mytailorisrich|5 years ago
Now that we have such a huge and interconnected population diversity will fade and adaptation will slow.
Metacelsus|5 years ago
chmod775|5 years ago
It would make sense if she specifically referred to Homo sapiens sapiens, but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them.
Also Homo sapiens sapiens have plenty of genetic diversity. Even just the number of easily observable environmental adaptions present in populations are countless (Sherpa, Bajau people, etc.)
As for COVID-19, most people are more-or-less unaffected by it. Our genetic diversity is working as intended.
adenozine|5 years ago
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.
gen220|5 years ago
It’s full of “and then tribe X invaded and the land of Y, took their women and enslaved their men”. Back and forth for centuries. This behavior was cyclical, inevitable, and universal, until violence was monopolized and institutionalized.
We’ve come a long way, I guess. Still have work to do.
abathur|5 years ago
https://www.smithsonianmag.com/science-nature/colored-pigmen...
https://en.wikipedia.org/wiki/Earliest_findings_for_hominid_...
There was inevitably conflict, but I'm skeptical of the "tendencies to rape and sexually conquer the opposition" framing. AFAIK there isn't much evidence for large amounts of inter-group violence. A paper like https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23751 lays out a contra case that the absence of evidence isn't evidence of absence--but I think it is a reason to be cautious about what we project back on those populations.
ves|5 years ago
082349872349872|5 years ago
https://history.stackexchange.com/questions/23975/what-was-t...
m463|5 years ago
Why couldn't they have been meaningful relationships?
carabiner|5 years ago
jimktrains2|5 years ago
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.
interestica|5 years ago
mc32|5 years ago
Ygg2|5 years ago
The act of separation would create new species. Not our drive to bone.
tzs|5 years ago
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.
[1] https://news.ycombinator.com/item?id=24686904
inglor_cz|5 years ago
AlotOfReading|5 years ago
sradman|5 years ago
> ...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.
[1] https://advances.sciencemag.org/content/6/8/eaay5483