More archaic human hanky panky..

Wibbs

http://www.bbc.co.uk/news/science-environment-12059564

Another hit for the complete replacement out of Africa side. And adds weight to my long held belief that there was an Eastern "Neanderthal"(I even got the location of most relict DNA may be found:eek: Colour me smug ). It made sense as it seemed daft to me that the only part of the world where erectus they said didn't evolve was Asia and they had been there for 2 million years. My next prediction is if they ever sequence erectus DNA from Asia, they'll find current populations there have some.

Yitzhak Rabin

Wow! This makes things much more interesting!! Pretty amazing find. Hope it doesn't lead to any sort of racist nonsense though.

Any chance I could borrow that crystal ball you have Wibbs? Wouldn't mind using it for predicting the lottery numbers...

darjeeling

The original mtDNA paper (thread here) indicated that the Denisovans were an outgroup from humans and Neanderthals. It looked as though ancestors of the Denisovans had left Africa around a million years ago - long after the first Homo erectus to leave Africa and spread into Asia, but also before the ancestors of Neanderthals and modern humans. Now the nuclear DNA data (ref) gives a different view. It suggests that Neanderthals and Denisovans are more closely related to each other than to modern humans. The N/D ancestors split from our modern human line around 800,000 years ago and went on in turn to split into Neanderthals and Denisovans around 640,000 years ago.

Denisovan contribution to modern humans seems to be limited to Melanesian people. It's already been established that non-African people have inherited a small proportion (around 2.5%) of their genome from Neanderthals (Science paper here). This new paper doesn't support an additional Denisovan contribution to non-Melanesian peoples. Melanesians, though, may have around 7.5% of Neanderthal & Denisovan genes. How the remote Melanesians acquired Denisovan genes whilst much nearer modern humans didn't remains to be seen, though it may hint that Denisovans were once very widespread.

The new Denisovan paper doesn't shed light on any possible contribution of Homo erectus to modern populations (the only relevant info comes from a Denisovan molar, which isn't much like an erectus one). Erectus migrated from Africa long before the Neanderthals / Denisovans. If erectus survived in Asia to overlap with the wave of modern humans coming out of Africa, they may too have interbred with these modern humans. However, we don't have any erectus DNA to test this.

Another incidental but notable finding in this paper is that while Vindija (Croatia) and Mezmaiskaya (Caucasus) Neanderthals were geographically distant, they were very closely related - much more so than modern human populations. This suggests a genetic bottleneck in - er - recent Neanderthal history.

Bus77II

That's really interesting and sort of nice that an ancient forgotton people are rememberd now.

thebouldwhacker

This is great news:)

rccaulfield

This might be huge! How much of the fossil did they find, he sounds unsure?

Wibbs

IIRC just a tooth and a fingerbone.

darjeeling

Wibbs wrote: »

IIRC just a tooth and a fingerbone.

Yes, that's all so far. Both come from different individuals - the tooth from a young adult and the finger bone from a juvenile, and the mtDNA genomes from tooth and finger differ at two positions (out of ~16,000).

The finger bone had remarkable DNA preservation - around 70% of the DNA they obtained was Denisovan, with the rest being bacterial, fungal and other stuff. For non-permafrost ancient DNA this is exceptional. In contrast, the Denisova molar gave a mere 0.2% of endogenous Denisovan DNA, while the Neanderthals sequenced so far have yielded 1% to 5% endogenous DNA.

The overall interpretation of the new results seems to be that the proto-Neanderthals on leaving Africa split into a Western, mainly European branch (Neanderthals), and an Eastern, mainly Asian one (Denisovans). Soon after Modern humans left Africa (100k-60k years ago), they bred with the Neanderthals - maybe in the Middle East. That's why all modern non-African populations have a low level of Neanderthal DNA. Later on, the founders of modern Melanesian populations bred with the Denisovans, though we don't know where this may have happened.

Edit: this seems to me unlikely to be the end of the story. As we turn up and sequence more fossils I wouldn't be surprised if we find other modern human populations have picked up small amounts of their genomes through similar interbreeding events.

rccaulfield

Rare interbreeding events tho no? I mean the Neandertals still went extinct of their own accord and we continued on, thats not for debate here is it? Why did the bbc guy have a skull on the table then, bit misleading i thought-even the article just says boones, sure thats what an ordinary man like myself wants to know straight away lie!

darjeeling

rccaulfield wrote: »

Rare interbreeding events tho no? I mean the Neandertals still went extinct of their own accord and we continued on, thats not for debate here is it? Why did the bbc guy have a skull on the table then, bit misleading i thought-even the article just says boones, sure thats what an ordinary man like myself wants to know straight away lie!

There are Chinese fossils, including skulls, whose origins have been much debated, and it may turn out that these are also Denisovan. That's what Chris Stringer (in the BBC video) thinks we'll find. The only two fossils that have been classified as Denisovan on the basis of DNA, though, are the two described in the Nature paper - the tip of a little finger, and a molar tooth.

I think most scientists are converging on the view that modern humans came out of Africa 100k to 60K years ago and spread around the world, occasionally interbreeding along the way with other distantly related humans. These distant relatives were the result of earlier migrations out of Africa, and they have now died out except where they left traces in our genomes. For now it looks as though perhaps around 10% or less of modern human genomes will turn out to come from the Neanderthals, Denisovans and other such extinct peoples.

Rubecula

Apparently up to about 50,000 years ago there was a third species of human living alongside Neanderthals and ourselves that has been given the tentative name of Denisovans.

They are thought to have interbred with both of the other species, and lived in the region of Siberia.

darjeeling

There are a couple of threads on the March 2010 mtDNA Denisovan genome paper (here) and the new nuclear genome paper (here).

'Denisovans' might have been a clearer thread title, but 'hanky panky' pulls in more punters.

Rubecula

I am sorry that I posted this thread before I had seen the Hanky Panky thread. My mistake. But blame it on the Christmas drinking LOL

steddyeddy

im not being bad but this was touted by asians for years its nothing new just something confirmed

Wibbs

I still reckon they haven't zeroed in on the Asian "Neanderthal". I further suspect much more parallel evolution into modern Humans in both Europe and Asia as well as the already known north east African populations. Hence why many Chinese scientists are convinced they have examples of Sapiens older than African Sapiens. IMHO they're not Sapiens, but more gracile asian neanderthal/Denisovan. European neanderthals were getting more gracile, more modern looking over time(and before the new lads from Africa showed up).

steddyeddy

Wibbs wrote: »

I still reckon they haven't zeroed in on the Asian "Neanderthal". I further suspect much more parallel evolution into modern Humans in both Europe and Asia as well as the already known north east African populations. Hence why many Chinese scientists are convinced they have examples of Sapiens older than African Sapiens. IMHO they're not Sapiens, but more gracile asian neanderthal/Denisovan. European neanderthals were getting more gracile, more modern looking over time(and before the new lads from Africa showed up).

thanks very much for putting that up wibbs, however every book i buy on human evolution becomes outdated faster than a pair of flares

Galvasean

With each new discovery we are far to quick to scream, "Missing Link Found!", "Out of X... Theory Shattered!". I think popular science reporting is too tabloidesque and sensationalist to admit that the human evolutionary tree is a tangled shrub, just like that of every other organism, not some sort of special case straight line. It's never that simple and everyone in science knows (or at least should) that.


PS: made it to 2 pages without me posting, the forum doth thrive, w00t!

darjeeling

I think this is something new. It shows that there was a distant Asian cousin of the Neanderthals that was not descended from the earlier East Asian Homo erectus, and that may once have been widespread.

This could indicate multiple waves of hominins coming out of Africa and spreading across Eurasia, replacing and on occasion interbreeding with the descendents of earlier waves. It may help us to reinterpret some of the Chinese hominin fossils that have rather been bones of contention, classified variously as early Homo sapiens or Homo heidelbergensis by different researchers. More sequencing will show!