New study reveals traces of unknown human ancestor

A new study of Neanderthal and Denisovan mTdna, reveals that Denisovans and Neanderthal split far earlier than was though, on the order of one million years ago
Even more surprising is the fact that the studies show the contribution of a previously unknown human ancestor.


From John Hawks' weblog,

and from the original article,

From the detailed genomes of both Neandertals and Denisovans, Pääbo and Montgomery Slatkin of the University of California, Berkeley, estimated that 17% of the Denisovan DNA was from the local Neandertals. And the comparison revealed another surprise: Four percent of the Denisovan genome comes from yet another, more ancient, human —"something unknown," Pääbo reported. "Getting better coverage and more genomes, you can start to see the networks of interactions in a world long ago," says David Kingsley, an evolutionary biologist at Stanford University in Palo Alto, California.

Meanwhile, the article sheds light on two interesting contradictions in the Denisova data. The analysis of the high-coverage data last fall [1] noted that the pinky bone genome is consistent with a very small long-term effective size, because of its limited genetic variation ("Denisova at high coverage". These results included a "drastic decline in size" around the time the Denisovans were estimated to have separated their population from the ancestors of living sub-Saharan Africans.

That result was curious in comparison with the mtDNA evidence. The Denisovan mtDNA is substantially more divergent from living human and Neandertal mtDNA, with an estimated time for the last common ancestor of mtDNA among these groups a bit more than a million years ago.

Now, we may be learning that the Denisovan genome itself represents different ancestral groups -- not only a more ancient "something unknown" population, but substantially the local Neandertals. That kind of mixture is not the population history described by papers on the Denisova genome so far. And a third Denisovan mtDNA from one of the third molars at the site is substantially different from the other two, pointing to greater mtDNA diversity within the Denisovan population than now known from either Neandertals or living people.

So Demisovans split off from the rest of us a million years ago, and they are the product of an unknown human ancestor, and they carried 17% local neanderthal DNA, fascinating stuff.

johnhawks.net...

That is some pretty interesting findings you have come across,punkinworks.Thanks for sharing that.I am off to do a little reading.

Peace,
K

That is very interesting Punkinworks, I'm annoyed that I agreed to go camping. Read all this Monday

It would be fascinating to know what happened to the Demisovans and if they followed a more successful path and are more technologically advanced, perhaps.

I love history and that fact that our history evolves is what intrigues me the most. Good for the guy that did this research.

Whenever academia gets thrown a curveball or gets turned on its head I smile. Because its almost like watching the bully get beat up .

Im not completely against the establishment as far as science and history but I believe there are things they dismiss simply because they are an inconvenience. I'll be interested to see what traction this gains in the next ten years or so. If they allow the lineage to be rewritten.

reply to post by punkinworks10


"7% of the Denisovan DNA was from the local Neandertals."

Is this due to interbreeding or a shared common ancestry?

I sometimes wonder what the big deal is about having the DNA of different human species in our genomes. If the "something unknown" happened to be a race of reptilian beings, then I'd be amazed... nay, delighted.

Originally posted by Nacirema
reply to post by punkinworks10

 

"7% of the Denisovan DNA was from the local Neandertals."

Is this due to interbreeding or a shared common ancestry?

As I read it, no it is not from shared ancestry. The neanderthal/denisovan split was a million years ago. And the Neanderthals in that cave are related to but distinct from Eurasian neanderthal
The most exciting part is the DNA from an unknown homonin. It shows that our past is far more complicated than current models allow for.
Im starting to lean toward a very early exit from Africa by a pre erectus ancestor, such austrolopithicus, that evolved into what we know of as Asian erectus, that colonized most of the reachable world, and eventually became us.

reply to post by punkinworks10

Im starting to lean toward a very early exit from Africa by a pre erectus ancestor, such austrolopithicus, that evolved into what we know of as Asian erectus, that colonized most of the reachable world, and eventually became us.

I have always thought that it was possible that the exodus from Africa was earlier as well.

Why not?
Sometimes they sell our ancestors a little short.

reply to post by kdog1982


The data is starting to show that the people the mainstream says left Africa and took the coastal route are a product of admixture between Africans and an Asian population, before they left Africa.

This paper supports Meyer et al.’s (2012) conclusion that East Asians are closer to Neandertals than Europeans. The difference is estimated on the order of 40%. This makes it unlikely that the 1-4% similarity between non-African human and Neandertal genomes, to the exclusion of African human genomes, is product of admixture between Neandertals and expanding modern humans. If this was the case, Europeans would have been more heavily admixed than East Asians. The asymmetrical connection between an archaic hominin species and a modern human population is further found in the case of Denisovans, whose remains are geographically located in East Asia but who show greater similarity to modern Melanesians than to East Asians. Wall et al. (2013) report that they failed to find any traces of admixture between Denisovans and East Asians (contra Skoglund & Jacobsson 2011) but they sampled only Japanese and Han Chinese, while Skoglund & Jacobsson reported the highest frequencies of Denisova alleles outside of Melanesia, in Southeast Asia and America (see more here). For the archaic admixture hypothesis to hold, one would need to postulate the dilution of Neandertal alleles in Europe and Denisovan alleles in East Asia by the subsequent (e.g., Neolithic) gene flow of populations unadmixed with Neandertals and Denisovans into these regions. The only place where these populations could have originated is Africa, but there’s no evidence for an excess of African alleles in East Asians and Europeans compared with Melanesians. Hence, the genomic pattern of association between Neandertals, Denisovans and non-African humans may be better explained as common descent, with African humans derived from non-African humans. Wall et al. (2013, 21) found evidence that can be interpreted precisely to such an effect:

“Also, we find evidence for a small but significant amount of Neanderthal admixture into the Maasai genomes (p ~ 0.03, Table S4). When compared to the Yoruba, the Maasai have a higher average D than the Luhya (Figure 3b, Table S4). When the Maasai are compared to all other African samples the average D is positive (Figure 3d). In addition, when East Asians and Europeans are compared to the Maasai, the average D’s are somewhat lower than when they are compared to either the Yoruba or Luhya.”

Table S4 shows that all of Wall et al.’s African samples have a Neandertal component, with Yoruba and Luhya training slightly behind Maasai. The paucity of Neandertal and Denisovan alleles in such “Paleoafricans” as Khoisans is better explained as product of admixture with African archaics that diluted the original Eurasia-derived gene pool of Africans

anthropogenesis.kinshipstudies.org... he-oldest-dog-news-from-around-the-web/

Combine that with the divergence time of some native Americans at 175k years ago, and the fact that the highest percentages of neanderthal and denisovan DNA in modern populations is in the new world, neanderthal for native north Americans and denisovan for native south Americans and the picture gets even muddier
Then you have the clearly not "modern humans" of the red deer cave people, mungo man #3 who' s most recent common ancestor was 125k years ago and was buried in Australia some 50-60k years ago, has no relationship to modern aboriginal Australians. Then there are the people of Kow swamp who do have a gentic relationship with modern aboriginals, but are physically closer to very late homo erectus in Indonesia.

reply to post by punkinworks10


I hate when they use percents.
We are only a percentage different from the other great apes.
So what does that mean exactly. How different were they?

reply to post by grey580


Well, an example I can give, regarding percentages... Males and Females of the same race are %99 percent the same. That %1 difference is pretty large if you think about it. From physically, hormonally, metabolically to psychologically (men are more rational/females more emotional thinkers) aspects that the sexes differentiate in.

I'm sure some one else can explain it better.

Very interesting info.

It's strange that they say modern humans are only 40 thousand years old. If we have been blended with other races that were much older, I will refer to myself as being related to the oldest one just as much as the modern man one. Think about it, at one point one of your ancestors was pure neanderthal if you possess the neanderthal gene. That means your great great great, etc.... grandpa or grandma was a neanderthal. So I consider my ancestors to go back as far as Neanderthals do in time. If they were this Devonian, and it was a million years, than my bloodline is over a million years old. I think that my ancestors have been on this world for a long time if I consider what they are saying is true.

I think it means the percentage of genes that relate to the ancestors in question.....
I think that it isnt too shocking when you look at the reports of hiant humans in the past.....
There are still reports of Bigfoots (hominids )today....
Thee are lots of evidences fior past peoples and civilisations as well as million year old man tracks with dinosaur tracks.....

Originally posted by rickymouse
Very interesting info.

It's strange that they say modern humans are only 40 thousand years old. If we have been blended with other races that were much older, I will refer to myself as being related to the oldest one just as much as the modern man one. Think about it, at one point one of your ancestors was pure neanderthal if you possess the neanderthal gene. That means your great great great, etc.... grandpa or grandma was a neanderthal. So I consider my ancestors to go back as far as Neanderthals do in time. If they were this Devonian, and it was a million years, than my bloodline is over a million years old. I think that my ancestors have been on this world for a long time if I consider what they are saying is true.

I mean, don't stop there...you can claim all the way back to proto-mammals and then further...all the way back. It's bazaar, but we're all related.

My great grand pappy (10+) was a Bonobo. O.o

Seriously, finds like this are for the history books. Soo much will be found within the next hundred years that we may get a grasp on how long we, Homo Sapiens Sapiens, have been around for. And, keeping fingers crossed, future findings won't be hidden.

Btw, I personally believe that us, as Humans now, have been around for close to a million years.

Something I consider, is that the richest environments, where life thrives the richest, are the areas where ancient remains are least likely to survive the ravages of time. The teaming abundance of organic matter would absorb the remains.

In the most barren locations, like deserts or frozen waste lands would preserve remains.

So we are unlikely to find the remains of ancient people that lived in the riches atmospheres.

And most likely to find the remains of those pushed out into the harshest environments.

reply to post by poet1b


That's a good theory however the land scape everywhere has changed throughout the millenia. Saharan Africa was once a grassland, Antarctica, who knows what that place was like 13,000 years ago but we do know at one point a lush rain forest had existed there. So, take your theory to search the places that once were fertile and lush.

But then again, time itself wastes away most traces of what once were.

Interesting that you post this today, I was just watching a new documentary along those same lines, which presents arguments pushing human history, fire use and skilled hunting techniques back hundreds of thousands of years. It's narrated by Deek Jackson, who many of you will associate with his own brand of current affairs and news shows, however this documentary had none of his cutting wit or punchlines, it's presented in a serious manner and gives food for thought. Enjoy.

reply to post by Sphota


Eventually we can track our origions back to a split where monkeys and apes took off in another direction. We did not evolve from apes, apes and us evolved from the same creature long ago. I assume long ago that we were of the bird family, just because of our attraction to colors and the desire of many of our young to dance. Maybe we are mutated dinosaurs of some kind.