CARTA: Ancient DNA and Human Evolution - The Landscape of Archaic Ancestry in Modern Humans
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- Опубліковано 1 сер 2016
- (Visit: www.uctv.tv/) In this talk, Sriram Sankararaman (UCLA) describes methods that enable us to map the locations of archaic ancestry in present-day humans. He then shows how the applications of these methods helps to understand the impact of Neandertal and Denisovan ancestry in present-day humans. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Science] [Show ID: 30975]
This is one of the more spectacularly impressive presentations at CARTA. Would love to hear more from this speaker anytime! (And, I've watched all CARTA videos over time)!
This was excellent.
A point he didn't make is that many of those "risk increasing genes" almost certainly were selected for because they conferred some sort of tangible advantage under the circumstances people lived in during past generations and still may.
By which i think if you mean the diabetic neanderthal gene, food scarcity adjustment and food storage, perhaps
Does the presence of Neanderthal and Denisiovan genes within populations vary because of selective pressures over time more than if gene flow occured in the first place? For example hypothetically if there was an even amount of initial gene flow between archaic and modern humans across the planet and then certain areas had greater selective pressure placed on hybrids leading to a decrease of those individuals within the population untill they were no longer present? this could mean hypothetically there was once Denisiovan and Neanderthals spread throughout, even in Africa then selective pressures eradicated them entirely in some areas, like Africa and we see remnant archaic genes within modern populations only in places where those selective pressures weren't as strong
I am now wondering if its possible to breed pure denisovians or neanderthals
Deep question. I bet they could. Eventually
The Homo Erectus could be added as one who might have mixed with humans.
maybe but, (per wikipedia) Homo Erectus are proposed to be the direct ancestors to several human species, such as H. heidelbergensis, H. antecessor, Neanderthals, Denisovans, and modern humans.
Very interesting lecture, but it doesn't tell us much about how our ancestors lived.
For a biological view of our evolution, google "ape and human evolution 2018 biology vs anthropocentrism".
The researcher is looking for the driving force behind certain locked in Gene's like foxp2. I can tell just from speech patterns a native american from either black or european speech. I would assume that their foxp2 is slightly earlier version than modern. To me this is the driving force in a community where the slightest difference can be noted. This would make the female a tiny bit more attractive in sexual selection also. In England only one base pair mutation in the foxp2 makes the entire family have speech problems but yet they persist. In turkey a group of a certain village walked on all fours instead of upright. I believe this was a cultural adaptation rather than a balance inner ear problem
This guy repeatedly makes the mistake of using the phrase “modern human” in reference to the “anatomically modern human” of 100-50Kbp, and compounds that with the bold assumption of a lack of archaic admixture in Sub-Saharan Africans.
The first actual modern humans were what are sometimes still referred to as Cro-Magnon.
At the point at which I am commenting he has also neglected to consider the possibility of further archaic admixture in “Oceanian” populations beyond Neanderthal and Denisovan.
DNA testing has found the tan-skinned Khoi San people of Southern Africa to be the closest present day analog to the anatomically moderns, which means that there is a lot more data required yet to tell us the ancestry of the remainder of African populations.
Such research is politically problematic so we may not see any results in the current policy climate.
Recent studies have found that some west african ethnicities have more than 7% archaic admixture. A population (it could be mende or mandinka) is estimated to have 11% archaic dna. In contrast khoi-san groups have almost no archaic dna and they are probablity the most closely related african group to eurasians. Ancient dna studies suggest that there was a clinal genetic structure in a zone from south to east africa before the migration of bantu farmers from west africa. Bantu dispersal changed the african gene structure so much that our closest relatives in africa are now assimilated and/or displaced by bantu migrants. But khoi-san still harbors much the ancient south-east african clinal variation.
When different species mix hybrids are created.
Is this not true?
So, are not Euros and Asians a hybridized species?
??? Hello. The correct term is race. Asians are a different race from European. the differences between the different races are presumably quite minor at the level of DNA.
The traditional definition of species for sexually reproducing organisms is that different species can't or don't interbreed and produce fertile offspring, otherwise, the boundaries between species would be vague. (Horses and Donkeys, for example, CAN interbreed, and have often been encouraged to, but their offspring are ALWAYS infertile.) Paleo-archaeological terminology breaks this rule because, until recently, it wasn't possible to tell whether or not different populations of hominids could interbreed. (That idea about selection against genes that cause still-births would be an example of partial uncompatibility, i.e., speciation in progress, though.) If you accept the idea that Neandertals and Devonians were not humans, then you call anyone with such ancestry "interspecies-hybrids", but that's kind of pointless because all modern humans are clearly the same spcies, and in fact have have much more in common with each other than any do with Neandertals or Devonians.
@@Mdebacle Thus rh+ ?
Of course. We are all thorough-going mongrels
And, then there is something very interesting going on with the autism spectrum, who have high expressions of Neanderthal genes. AS have been historically isolated by the Neurotypical modern humans, and typically only interbreed with each other and have for a very long historical time. It would be very interesting to see how this works out on the FOXP2 gene desert, since autistics brains are wired for a more Neanderthal version of language that is highly visual. Just because two different types inhabit the same geographic areas doesn't mean they are not different species. As a rule, Neurotypicals refuse to integrate with autistics, and one only has to look as far as the tests bar admissions committees use to keep autistics out of the legal profession and governmental power structure to see this speciazation isolation.
Duh
Who isn't in the Study? Africans and Jews!!!
This explained where Cain got his wives.
Please! Studying Human Evolution at the level of DNA is way, way too premature. NOT until Human Evolution has been completely mapped out at the morphological level would tracing evolution to the level of DNA be even remotely possible.