More evidence published that Neanderthals were little different from "modern humans"

[innonimatu]

Paintings dated 64000 found in Spain shown that cave painting did not start with the so-called "modern humans", but existed already before their assumed migration into Europe.

Discovery of cave paintings and decorated shells reveals Neanderthals were artists

The discovery of paintings made over 64,000 years ago in Spanish caves suggests Neanderthals possessed creativity and the ability to think symbolically, like modern humans.

Among the works on display in these caves were paintings of animals, dots and geometric patterns, as well as hand stencils, hand prints and engravings.

“Our results show that the paintings we dated are, by far, the oldest known cave art in the world, and were created at least 20,000 years before modern humans arrived in Europe from Africa therefore they must have been painted by Neanderthals.”

The work was carried out by a team of scientists from several European institutions, and their results were published in the journal Science.
[...]
the scientists working on the newly discovered paintings used state-of-the-art uranium-thorium dating to provide more accurate age estimates.

They analysed calcium carbonate crusts that had developed over the cave paintings, allowing them to date the art without damaging it.

As artworks were found in caves 700 kilometres apart, and spanning a period of 25,000 years, the practice appears to have been a widespread cultural tradition among Neanderthals.

To be clear, assumed is my own criticism of a theory of human evolution that should have been shelved due to new evidence years ago. I do not believe that a total replacement of the population of Europe some 40000 years ago happened, or that any credible evidence of such replacement has ever been produced to justify the hold such a theory has had during the last decades. Theories on pre-history always rested on exceedingly thin evidence of few archaeological remains. Fortunately we keep adding to that record, things should improve!

Human evolution and the birth of human "culture" seems to me more likely to have been a continuum from a far more distant time, with populations moving and mixing in all directions for nearly a million years.

 

[Arakhor]

I was under the impression that genetic studies on Neanderthal remains indicates that we (Europeans) share less than 5% of our DNA with our northern cousins. What's more, unless I'm missing something very obvious, since there are no Neanderthals alive today, by default there must have been a total replacement of the humans living in Europe.

 

[Ferocitus]

Paintings dated 64000 found in Spain shown that cave painting did not start with the so-called "modern humans", but existed already before their assumed migration into Europe.

Discovery of cave paintings and decorated shells reveals Neanderthals were artists

They were very sensitive little snowflakes, though.

 

[Hrothbern]

5% is a fair bit though.

I was under the impression that, over the last decade or so, the general consensus was that homo sapiens had interbred and dominated the Neanderthals, rather than wiping them out. What, to me at least, isn't clear is whether the domination happened through violence, some kind cultural assimilation, or if homo sapiens just outbred them to the point of irrelevance.

None of that 5% is on the Y-chromosome
A. That could be sheer coincidence ofc.
B. It could also be that male Neandertaler DNA (on that Y-chromosome) was a negative evolutionary factor for hybrid offspring (there are some findings there)
C. It could also be that female Neandertaler were caught as wife
D. or in some conflicts only male Neandertaler were killed.

All 4 factors could still fit a in general peaceful situation.
And in order to get that 5% Neandertaler DNA bred into our genes C and/or D must have happened a lot. Even 100% peacefull would be possible with B.

 

[innonimatu]

Does anyone here know on what evidence were those 5% number for DNA mixing based?

Afaik DNA that old can only be extracted already quite degraded. In this I always tend to skepticism until I can read about the data used.

 

[Arakhor]

I believe that the Neanderthal genome has been sequenced, so it would (presumably) be a simple case of mathematics when comparing our genomes. (I don't know for certain though.)

 

[innonimatu]

An example of how DNA data has been misused and abused to draw false "knowledge":

The earlier genomic analysis of the female Altai Neanderthal showed that her parents were half-siblings, which got scientists thinking that Neanderthals made it a habit of breeding with immediate family members. But the Vindija 33.19 genome is different; her parents were not as closely related, so we can no longer say that extreme inbreeding is a common fixture of the Neanderthals.

A single specimen had been used to claim that "Neanderthals made it a habit of breeding with immediate family members". A single other specimen invalidated that. We're talking about very sparse evidence here, being used to back various theories.

I believe it will take data from thousands of individual remains to make any reliable guess about what really happened. And even thousands are very few to map populations across the whole eurasian space!
Until then we have theories, different people favor different theories, but we should not be talking as if we already know what happened.

Genome sequencing and comparison relies heavily on statistical analysis. There have been scandals over misuse of "DNA evidence" in criminal cases where the source material was recent and well preserved. I do expect better work standards from research teams, but the material they work with is much worse...

 

[Arakhor]

Science is all about makng hypotheses, forming theories based on those hypotheses and then perhaps disproving those theories. No one is suggesting that these claims are graven in stone, presumably.

 

[innonimatu]

No indeed. But it gets dangerous for researcher's credibility when press releases and disseminate theories and a few years later they have to be thrown away.

Back in 2010 this was the summary of the first study that purported to have reconstructed a (though press releases went on to say "the") Neanderthal genome:

On page 710 of this week's issue of Science, an international team of researchers presents their first detailed analysis of the draft sequence of the Neandertal genome, which now includes more than 3 billion nucleotides collected from the bones of three female Neandertals who lived in Croatia more than 38,000 years ago. By comparing this composite Neandertal genome with the complete genomes of five living humans from different parts of the world, the researchers found that both Europeans and Asians share 1% to 4% of their nuclear DNA with Neandertals. But Africans do not. This suggests that early modern humans interbred with Neandertals after moderns left Africa, but before they spread into Asia and Europe. In a separate paper (p. 723), the team describes and successfully tests a new method for filling in gaps in the rough draft of the genome.

Notice the terms "draft" and "filling the gaps". Notice also that they claimed to have sequenced DNA from one individual, and compared it with 5 modern individuals. In a medical study this would be absolute garbage, a single samples just can't prove anything about a population. It was useful because it produced new information, of course. But claiming that "both Europeans and Asians share 1% to 4% of their nuclear DNA with Neandertals" from this study of one individual is scientific garbage.
The summary should have been much more cautious and conditional in presenting results, to avoid these being repeated as some categorical discovery and later shown wrong. To be fair the abstract is more cautions, but the press misrepresents it, and universities are only too happy to encourage that in order to get short-term publicity.

 

[innonimatu]

I'm kind of answering myself now that I searched, but I guess it'll be interesting for anyone reading the tread to quote here some pieces from this study.

On the difficulty of deciding what is a "match":

A challenge in detecting signals of gene flow between Neandertals and modern human ancestors is that the two groups share common ancestors within the last 500,000 years, which is no deeper than the nuclear DNA sequence variation within present-day humans. Thus, even if no gene flow occurred, in many segments of the genome, Neandertals are expected to be more closely related to some present-day humans than they are to each other (20). However, if Neandertals are, on average across many independent regions of the genome, more closely related to present-day humans in certain parts of the world than in others, this would strongly suggest that Neandertals exchanged parts of their genome with the ancestors of these groups.

On the degradation of ancient DNA:

Several features of DNA extracted from Late Pleistocene remains make its study challenging. The DNA is invariably degraded to a small average size of less than 200 base pairs (bp) (21, 22), it is chemically modified (21, 23–26), and extracts almost always contain only small amounts of endogenous DNA but large amounts of DNA from microbial organisms that colonized the specimens after death. Over the past 20 years, methods for ancient DNA retrieval have been developed (21, 22), largely based on the polymerase chain reaction (PCR) (27). In the case of the nuclear genome of Neandertals, four short gene sequences have been determined by PCR: fragments of the MC1R gene involved in skin pigmentation (28), a segment of the FOXP2 gene involved in speech and language (29), parts of the ABO blood group locus (30), and a taste receptor gene (31). However, although PCR of ancient DNA can be multiplexed (32), it does not allow the retrieval of a large proportion of the genome of an organism.

On comparing the DNA:

Average DNA divergence between Neandertals and humans. To estimate the DNA sequence divergence per base pair between the genomes of Neandertals and the reference human genome sequence, we generated three-way alignments between the Neandertal, human, and chimpanzee genomes, filtering out genomic regions that may be duplicated in either humans or chimpanzees (SOM Text 10) and using an inferred genome sequence of the common ancestor of humans and chimpanzees as a reference (51) to avoid potential biases (39). We then counted the number of substitutions specific to the Neandertal, the human, and the chimpanzee genomes (Fig. 2). The overall number of substitutions unique to the Neandertal genome is about 30 times as high as on the human lineage. Because these are largely due to transitions resulting from deamination of cytosine residues in the Neandertal DNA, we restricted the divergence estimates to transversions. We then observed four to six times as many on the Neandertal as on the human lineage, probably due to sequencing errors in the low-coverage Neandertal DNA sequences. The numbers of transversions on the human lineage, as well as those on the lineage from the Neandertal-human ancestor to the chimpanzee, were used to estimate the average divergence between DNA sequences in Neandertals and present-day humans, as a fraction of the lineage from the human reference genome to the common ancestor of Neandertals, humans, and chimpanzees. For autosomes, this was 12.7% for each of the three bones analyzed. For the X chromosome, it was 11.9 to 12.4% (table S26). Assuming an average DNA divergence of 6.5 million years between the human and chimpanzee genomes (52), this results in a point estimate for the average divergence of Neandertal and modern human autosomal DNA sequences of 825,000 years. We caution that this is only a rough estimate because of the uncertainty about the time of divergence of humans and chimpanzees.

Still reading the paper, I'm liking the actual work. Too bad it gets easily misrepresented in the press.

Talking about the misuse and misrepresentation of scientific studies made me recall a recent example, but this one is just about very modern humans two studies with similar statistical conclusions produced these headlines in our amazingly ignorant (when not outright deceitful) press:

and the people wonder how "populists" can get appreciated by attacking the press...

 

[Arakhor]

This isn't really about Neanderthals, but it is about new developments in the early history of man.

 

[innonimatu]

And on the early history of man, we keep discovering how little we have actually discovered so far. Stone tools found in east Asia dated to 2.1 million years ago. The pre-history of mankind seems to older than many people had assumed.

These finds tend to be dismissed as mistakes, but evidence is piling up as more remote areas are explored more carefully. Nice that there are new things to discover in the world yet.

I think that even these are only timid steps on the way to admitting that our species evolved different lines and kept mixing over perhaps a couple million years years and an area that included all of the temperate region of the "old world".

The origins of our species have long been traced to east Africa, where the world’s oldest undisputed Homo sapiens fossils were discovered. About 300,000 years ago, the story went, a group of primitive humans there underwent a series of genetic and cultural shifts that set them on a unique evolutionary path that resulted in everyone alive today.

However, a team of prominent scientists is now calling for a rewriting of this traditional narrative, based on a comprehensive survey of fossil, archaeological and genetic evidence. Instead, the international team argue, the distinctive features that make us human emerged mosaic-like across different populations spanning the entire African continent. Only after tens or hundreds of thousands of years of interbreeding and cultural exchange between these semi-isolated groups, did the fully fledged modern human come into being.

 

[Ferocitus]

Human evolution and the birth of human "culture" seems to me more likely to have been a continuum from a far more distant time, with populations moving and mixing in all directions for nearly a million years.

There are so many threads to the evolution of homo sapiens that a paper by 23
authors from a variety of fields was released yesterday that tries to develop a
forward for the next few years...

Rethinking Homo sapiens? The story of our origins gets dizzyingly complicated
https://theconversation.com/rethink...our-origins-gets-dizzyingly-complicated-99760
Extract:
So profound is the shift underway in human origins science that it’s seen the unusual step of a team of 23 researchers (led by Eleanor Scerri of the University of Oxford) publish today’s new synthesis of the evidence – and in doing so embrace the emerging picture of complexity and ditch the old simplistic ideas. Among their ranks are archaeologists, anthropologists, geneticists and climate specialists.

It reads like a manifesto, and outlines the major new research directions archaeology should follow to solve our puzzling origins. A key message is that none of these disciplines on their own is capable of doing it and going it alone. That approach only leads to us grasping for simple answers to complex questions.

A pdf of the paper can be downloaded from:
https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(18)30117-4.pdf

 

[Arakhor]

It's all very interesting. Palaeoanthropology is one of those fields that's long fascinated me, but it's not a job I'd actually want to do.

 

[Ferocitus]

It's all very interesting. Palaeoanthropology is one of those fields that's long fascinated me, but it's not a job I'd actually want to do.

Obviously you're not one of my generation, so don't try to dig what we all say.

 

[Hrothbern]

Evolution is very much about surviving in your habitat, surviving the famines and growing fast during the good years. DNA evolving so that both are handled well.
DNA evolving into a Jack of all Trades to populate more kinds of habitats mostly not so succesfull other than being a "high energy state" transition phase, possible in nice climate situations before traditional population has saturated it, and allowing for falling back in the old subset of genes in the old habitat, but also falling sideways in a new subset of genes for a new kind of habitat.
It is much less a military logistic campaign gaining new ground with the latest DNA tech upgrade.

Sweet spot hopping getting more attention now in the theories.
The big trading market of the "new techs", the new genes, a long process parallel.

With our genes not fully adapted to the changed food sources in Eurasia (we had to change/add metabolic pathways to handle vegetables with other poisons, other defensive mechanism against local herbivores, parasites, bacteria, adapt to less sun and higher latitudes sunlight variation, etc, etc),
our food sources in Eurasia were more limited and only sweet spots, with an abundancy of food sources to choose from, including low burden for basics as shelter, fresh water, etc, were "good enough" to survive "bad" climate periods and grow population in "good" climate periods.
In this background our genes evolved to the local food, not to survive, but because it generated more ofspring.

Every "good" climate period a phase, where the best adapted grew faster, a phase to hop to new sweet spots, the best adapted genes having the most capacity to do so, and to interchange genes, enabling combining the best ones for the common pool. The "bad" periods again nice to get rid of genes that were less effective, on their own, or in a combination.

 

[innonimatu]

This is kind of my pet thread, so...

New DNA evidence of cross between Neanderthal an Denisovan populations. Didn't check the source for papers and the quality of the work.

 

[Arakhor]

I read the related article on the BBC. It's a shame that none of our cousins survived to inherit the world with us.

 

[Lexicus]

I read the related article on the BBC. It's a shame that none of our cousins survived to inherit the world with us.

Some of their DNA survives in us. This means it's not exactly the case that they all just up and died.

 

[Imaus]

I wonder how this ties into H. Idatu and the Denisovans as well.