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On the trail of the Denisovans
- kgeist 3y agoThe article says: >In Tibet, Dr. Huerta-Sánchez and her colleagues have found a Denisovan gene that helps people survive at high altitudes Can't it be simply convergent evolution?
- rhelz 3y agoAnything is possible, but it would kind of be like finding two pc-clones, both which contained a copy of MS-DOS, and concluding that each was independently programmed. For the kinds of arguments which scientists use to support these claims, see "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" by Emilia Huerta-Sánchez, et al.
- kryptiskt 3y agoIt would be weird to have the same DNA sequence from convergent evolution, since even if evolution converged on exactly the same protein (unlikely as that may be), most amino acids in the sequence can be represented by several different DNA triplets and there is absolutely no reason why it should converge on the same triplets.
- goles 3y agohttps://archive.is/TXTdK https://archive.is/TXTdK
- rhelz 3y agoNo doubt there are many, many other varieties of humans which we'll never know about because we'll never find any bones. What chilling is that shows very clearly that humans can go extinct. In fact, humans go extinct all the time: 50,000 years ago, we shared the earth with at least 5 different varieties of humans (Homo Neanterthalensis, Homo Denisova, Homo Naledi, Homo Florensiensis, and Homo Luzenenensis). Probably also some late surviving populations of Homo Erectus and Homo Rudolfensis. Almost certainly more we'll never know about. Since the last ice age we've been dropping like flies. In fact, we're the only humans left. And what with climate change, accidental nuclear war, or the singularity looming, we are arguably in a more precarious position than we've ever been.
- huytersd 3y agoHumans have never had the numbers they’ve had right now. It would be very hard to eradicate 8 billion individual organisms.
- deleted 3y ago[deleted]
- Simon_ORourke 3y agoWhat do you mean hard? I do this all the time with some bleach and a scrubbing brush.
- huytersd 3y agoGlobal scale bleach events are rare.
- AndrewKemendo 3y agoThis offered me a good laugh. Thank you.
- account-5 3y agoWe're trying our best though. EDIT: for those downvoting, I'd like to discuss why you don't agree. I mean, climate change, war, etc. What else can you call it?
- echelon 3y agoNo amount of climate change short of Venusian runaway heating will scour the earth of humans. If we launch all of our nukes, we might collapse civilization, but even that would likely leave humans around. We might get stuck in our gravity well for a long time, though. Whatever makes us go extinct will either be cosmic or something we haven't invented yet.
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- verisimi 3y ago> In a new review paper, anthropologists tally all of the fossils that have been clearly identified as Denisovan since the first discovery in 2010. The entire list consists of half a broken jaw, a finger bone, a skull fragment, three loose teeth and four other chips of bone. Right... is that enough? Then: > “What we have found out about Denisovans is that, from a behavioral perspective, they were much more like modern humans,” said Laura Shackelford, a paleoanthropologist at the University of Illinois. How can anyone make those sorts of leaps, on the basis of a tooth and some bone chips? > Dr. Shackelford said findings like these raised the possibility that Denisovans and modern humans coexisted and interacted for tens of thousands of years — though whether they communicated is unclear. “That’s really going down the rabbit hole,” Dr. Shackelford said. What he's saying is we can't tell if these purported species communicated, on the basis of what seems to me to be super lightweight evidence. He said "communicate"!
- WalterBright 3y agoHow does one tell a skull fragment is a different species?
- verisimi 3y agoVia DNA, it says. But I can't get to the bottom of why DNA analysis is considered to be solid, when there are examples of it being quite flawed, eg with these twin sisters: https://www.youtube.com/watch?v=Isa5c1p6aC0 https://www.youtube.com/watch?v=Isa5c1p6aC0 Someone said that these consumer outfits are known to be trash - but I presumed that all DNA tests would end up going to the same labs, and those labs would use the same principles to test. There is quite a big question for me about the validity of DNA as evidence, when it is possible to show how some tests fail.
- Tagbert 3y agoAutomatic genetic testing in a commercial lab is not the same thing as controlled analysis by anthropologists and geneticists.
- profsummergig 3y agoBecause Neanderthals were discovered in Europe, people think Neanderthal DNA is a marker of European ancestry. East and South Asians, and Native Americans have higher Neanderthal DNA than Europeans. Source: https://images.app.goo.gl/Q1JLpT6MqiubCHq18 https://images.app.goo.gl/Q1JLpT6MqiubCHq18
- stainablesteel 3y agoasians have a lot of denisovan dna too, and there are bone fragments originally attributed to denisovans that were found by DNA to be a 50/50 denisovan/neanderthal mix somewhere in the ballpark of modern uyghur territory atm iirc (some of the only denisovan pieces ever found i believe) hybrids are usually unlikely to be able to reproduce but its not impossible depending on how distant they were, and we simply dont have enough evidence to deny they could have so it could have been neanderthal-denisovan hybrids that went across asia for all we know
- huytersd 3y agoThat’s East Asian. South Asians generally just have very high Neanderthal ancestors.
- MilStdJunkie 3y agoThere's a non-zero chance that many of the asiatic H. Erectus[0] found during the late 19th and early 20th century are, in fact, Denisovans or their relatives, but were recovered in a period where our ideas about human migration were quite different from today's . . and long before genetic analysis[1]. When the remains are examined in their entirety, the variations are quite extreme, with brain sizes ranging from near-ape to practically modern. [0] i.e., Java Man [1] Revealing peoples like the Andaman islanders as having a high proportion of non-Sapiens non-neanderthal DNA, something that would fit into a 19th century anthropology not at all.
- thriftwy 3y ago[flagged]
- thriftwy 3y ago[flagged]
- gpapilion 3y agoOne thing I’ve been thinking about lately is whether there is the possibility of a frozen Denisovan or Neanderthal falling out of the permafrost somewhere in Siberia. The oldest mammoth found is around 30000 years old, so maybe a bit out of the ballpark. It seems like it would answer so many questions.
- stainablesteel 3y agomaybe somewhere in the himalayas or the extended eurasian mountain range for the denisovans, they were closer to that area siberia i doubt though, and probably not neanderthals
- angiosperm 3y agoDuring much of the Pleistocene, a million square miles of what is now sea floor north of Java all the way to Viet Nam and northeast to Korea, was prime bottom land rivaling Africa in richness and diversity. It would be unsurprising if that was where Denisovans flourished.