Tag Archives: Neanderthals

A Draft Sequence of the Neandertal Genome

A Draft Sequence of the Neandertal Genome

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

To cut a long story short…

The authors suggest that non-Africans having about 1-4% Neanderthal ancestry is the most likely explanation for the variation in the DNA they have found. It’s not an absolute. A much less likely but not impossible scenarios is that the variation is due to population structure in Africa prior to the OOA, which may relate with the earlier separation of the ancestors of modern Africans and non-Africans inside Africa, although John Hawkes thinks this is so unlikely he was surprised they gave it space on the paper.

But, considering the number of genes in non Africans that have a time depth that is considerably older than the OOA movement (over 1 million years on one in one study by Hammer et al), and I think there is now decent evidence for Neanderthal ancestry in non-Africans.

I have some issues with the paper. Modern humans were in the near East about 120k ago, keeping company with Neanderthals for many millennia, but the interbreeding date comes out at 80,000 to 50,000 years. What were they doing with the rest of the time?

Such a scenario is compatible with the archaeological record, which shows that modern humans appeared in the Middle East before 100,000 years ago whereas the Neandertals existed in the same region after this time, probably until 50,000 years ago.

  And they observe that modern Europeans don’t seem to have a higher amount of Neanderthal ancestry than anyone else. But then they add:

 This possibility can be addressed by the determination of genome sequences from pre agricultural early modern humans in Europe (85). It is also possible that if the expansion of modern humans occurred differently in Europe than in the Middle East, for example by already large populations interacting with Neandertals, then there may be little or no trace of any gene flow in present-day Europeans even if interbreeding occurred.  

Which is what I suspect is more likely. I’d also like to address the apparent lack of modern human ancestry in the Neanderthals: well a quick look at the dates of the remains sampled; not younger than 38,000 BP. Which is prior to the date modern humans started to move into that part of Europe. Possibly a future investigation of later dated remains would show some AMH ancestry in them, as their appearance suugests they may be hybrids. I think the  Lagar Velho specimen would be a possible source, although it would be a pity to damage the specimen, possibly the Gorham’s Cave bones could yield relevant information.

Neanderthals ‘had sex’ with modern man

Neanderthals ‘had sex’ with modern man

From an article in the Times

Modern humans and Neanderthals had sex across the species barrier, according to a leading geneticist who is overseeing a project to compare their genomes.

Professor Svante Paabo, director of genetics at the renowned Max Planck Institute for Evolutionary Anthropology in Leipzig, will shortly publish his analysis of the entire Neanderthal genome, using DNA retrieved from fossils. He aims to compare it with the genomes of modern humans and chimpanzees to work out the ancestry of all three species.

I can’t say I’m surprised to see this. Later (transitional) Neanderthals picked up modern human traits like chins and more complex burial rituals, and a few sets of remains do look hybrid. If you look at the more recent reconstructions such as ‘Wilma’ (from Nat geo), they don’t look massively different to modern humans.

In addition to this there are numerous DNA studies that suggest a low level on Neanderthal contribution to Europeans (5% or less seems the norm) even though Neanderthal mitochondrial DNA and Y chromosomes are absent.

Out of Africa again and again

Possible Ancestral Structure in Human Populations

Archaic admixture in the human genome

Detecting ancient admixture and estimating demographic parameters in multiple human populations

There are a few more, but you get the point.

From looking at the difference between Mesolithic and modern Europeans mt DNA, I know that it would be easy to lose a small minority contributor through drift, and it’s unlikely that (as a group being exterminated)  male Neanderthals would have made any kind of traceable contribution, as females may be absorbed from lower status groups, but males usually aren’t.

Theres also a  vid which mentions the subject by Prof Paabo on the subject on Youtube. I guess we’ll just have to wait and see.

Who made the early Aurignacian? The dental evidence.

Who made the early Aurignacian? Evidence from isolated teeth.

Page 5

S.E. Bailey. Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology (Leipzig), Department of
Anthropology, New York University.

Neandertals and anatomically modern humans overlapped in Europe between 45- and 30,000 BP. Unfortunately, the human fossil record during this important time period is sparse. What is preserved is fragmentary and consists primarily of jaws and isolated teeth. This has led some to question whether we can determine if Neandertals or anatomically modern humans were responsible for the early Aurignacian. The goals of this study were, first, to investigate whether root lengths can help differentiate these two taxa; and second, to combine these data with tooth crown traits to assess the taxonomic affiliation of isolated teeth from two early Aurignacian sites (Brassempouy and La Ferrassie).

Root lengths were measured from the lingual aspect of permanent teeth of Neandertals (maximum n=15) and Upper Paleolithic modern humans (maximum n=10). The student’s t-test showed that the mean root lengths of I1, I2, C’, I1, I2, C, P3, P4 and M2 were significantly longer in Neandertals than in Upper Paleolithic moderns (p<0.05), with no overlap in the ranges of I1, I1, C’, and P4. At Brassempouy, the root lengths of the two I1s, C’ and M2 fall more than three standard deviations below the Neandertal mean. Likewise, the single I1 from Le Ferrassie possesses a root that is too short to be considered Neandertal. Additionally, the tooth crowns at both Brassempouy and La Ferrassie lack any diagnostically Neandertal traits. Thus, the preponderance of dental evidence suggests that anatomically modern humans, not Neandertals, are associated with these early Aurignacian sites.

And also by the same author… 

Who made the Early Aurignacian? A Reconsideration of the Brassempouy Dental Remains

The dental human remains from the early Aurignacian layers of Brassempouy (Landes) have been recently described by Henry-Gambier et al. (2004). We provide a critical re-assessment of the features that have led these authors to conclude that the taxonomic status of these fossils is uncertain. Although the works of one of us (S.B.) have been partly used and cited by Henry-Gambier et al. (2004), we disagree with the conclusions that have been drawn from them. In our view and based on the available evidence, the early Aurignacian dental remains from Brassempouy are unambiguously modern in their anatomy. They indeed provide further evidence that the makers of the ancient Aurignacian were early anatomically modern Europeans.

 The second link contains a more complete article.I’ll refrain from mentioning that if the remains are so similar at times that they can only be categorised as one or the other with difficulty.. surely this would suggest some overlap between the two genetically as well as physically.

Neanderthals could have died out because their bodies overheated

Neanderthals may have died out because their bodies overheated as the Earth grew warmer
By Richard Gray, Science Correspondent 

 Neanderthal DNA reveals key differences from modern humans. Analysis of DNA obtained from Neanderthal remains has revealed key differences from modern humans that suggest their bodies produced excess heat.

While in the cold climate of an ice age this would have provided the species with an advantage, as the earth warmed they would have been less able to cope. Ultimately this would have caused their extinction around 24,000 years ago.

Scientists at Newcastle University have put forward the theory after examining a particular form of genetic material which was obtained from the fossilised bones of Neanderthals.

By comparing it with that found in modern humans, they discovered that Neanderthals had key differences in the sections responsible for producing energy in all living cells.

Professor Patrick Chinnery, a neurogeneticist at Newcastle University, believes the differences in this mitochondrial DNA could have caused Neanderthals to be inefficient at producing energy, meaning their cells leaked heat.

He said: “The question is why did Neanderthals disappear? There are lots of explanations to do with changes in climate and the food supply.

“Differences in these mitochondrial DNA sequences might explain why modern humans were able to survive while Neanderthals were not.

“We compared mitochondrial DNA sequences from Neanderthals that have been obtained by other researchers with a huge database of human sequences from around the world to see how different it was from modern humans.

“We found a number of differences within a certain part of the mitochondrial DNA that were quite unlike anything we see in modern humans.

“It is difficult to get a definitive answer, as it is rather like looking through a misty window. We can only get clues to what went on.”

Mitochondria are tiny structures found inside all living cells and are the biological power stations that produce the energy cells need to survive by converting sugar from food into energy.

The research by Professor Chinnery, which was recently presented at a conference held by the American Society on Human Genetics, is the latest attempt to find out why our ancient cousins died out.

Scientists have also been attempting to read the entire Neanderthal genome in the hope that it will shed more light on the differences between them and modern humans.

Recent work by scientists at the Max Planck Institute in Germany revealed that Neanderthals shared a language gene that is only found in modern humans. The controversial findings raised the debate about whether Neanderthals were capable of speech.

Neanderthals are thought to have evolved from a common ancestor shared with modern humans around 400,000 years ago. It is thought they died out around 10,000 years after modern humans began spreading in to Europe.

There is a great deal of debate about what actually sealed Neanderthals fate, with the changing climate, dwindling food supplies and modern humans themselves all being blamed for killing the species off.

Technically, this would really only account for their mt DNA becoming extinct. Which would explain why it is a no-show in the modern genome even though lots of other archaic genes seem to have made an appearance. A New Scientist article on the same subject here.

Blogging will be pretty thin on the ground here until after Christmas, as I shall be busy with my kids and festive stuff. So have a Merry Christmas, and sorry of your comments don’t register for a while, as I shan’t be around for most of the rest of the week.

Neanderthals in Okladnikov cave Siberia

Neanderthals roamed as far as Siberia 

 DNA extracted from skeletal remains has shown that Neanderthals roamed some 2000 kilometres further east than previously thought.

Researchers say the genetic sequence of an adolescent Neanderthal found in southern Siberia closely matches that of Neanderthals found in western Europe, suggesting that this close relative of modern humans migrated very long distances.

Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues examined skeletal remains found in the Okladnikov cave in the Altai Mountains and dated as between 30,000 and 38,000 years old . Until now, archaeologists have been unable to determine whether the remains belonged to Neanderthals or another species of extinct hominid because the bones are too fragmented.

Pääbo and his colleagues took 200 milligram samples of bone from the adolescent. After dissolving the mineral component of the bone, the team succeeded in extracting DNA from mitochondria – parts of the cell that produce energy.

Near-perfect match
After sequencing a short fragment of this DNA, the team compared it with that of several Neanderthals found in Europe. They discovered that it matched DNA recovered from remains found in Belgium almost perfectly. The match was “quite a bit of a surprise”, according to Pääbo, since the new evidence extends the territory of this hominid some 2000 kilometres further east.

“It means that Neanderthals were a bit more adaptable than some people give them credit for,” says Jeffrey McKee at Ohio State University in Columbus, Ohio, US.

Archaeologists had previously thought that Neanderthals’ range only extended as far as modern-day Uzbekistan. This was based on a distinctly Neanderthal skull – with a prominent brow and large nasal area – recovered from the Teshik-Tash cave in the south-east of the country.

The study may not settle the debate over Neanderthal’s range definitively, though. Eric Trinkaus at Washington University in St Louis, Missouri, US, questions whether it definitively proves the Okladnikov bones to be those of Neanderthals.

Trinkaus suggests that other species of hominids could have had the same mitochondrial DNA sequence as Neanderthals. The mitochondrial sequence found by Pääbo’s team can be used to definitively identify individuals as Neanderthals only after scientists study the mitochondrial DNA of other archaic hominids too, he says

And here is a link to the abstract. Old news, but I’m trying to keep all the neanderthal info I can find on my blog for easy access, as my memory is suffering a bit lately from the MS.

The evolution of non-metric dental variation in Europe

The evolution of non-metric dental variation in Europe
Shara E. Bailey

 The potential for dental morphology to answer questions about human evolution in the Middle to Late Pleistocene has only recently begun to be appreciated. Non-metric dental traits provide useful information for taxonomic diagnosis as well as for assessing biological relationships among living and ancient populations. This study uses dental morphology to assess temporal change in Europe. Homo erectus serves as the presumptive primitive condition for later humans and change over time is assessed by calculating estimates of divergence between groups based on the mean measure of divergence multivariate statistic. The samples include Homo erectus (n = 12), early modern humans from Africa and West Asia (n = 12), early Neandertals (n = 16), late Neandertals (n = 20), Upper Paleolithic Europeans (n = 28) and contemporary Europeans (n = 47). The results show a marked disruption in continuity from early modern to later modern humans when Neandertals are incorporated into the temporal sequence. If Neandertals are left out of the sequence the change in divergence values conforms to expectations for gradual evolution toward the modern human condition (e.g., distance values get progressively smaller through time). At minimum this should set to rest any idea that modern Europeans evolved directly from Neandertal ancestors. Late Neandertals are somewhat less ‘specialized’ than early Neandertals; the implications of this finding are discussed.

A close up of Neanderthal teeth from Krapina, showing a high degree of shovelling. According to an observation by Coon, the teeth of the Grimaldi boy were quite similar to the teeth from Krapina in some respects.

One previous study of teeth concluded…

Crummett (1994) examined the first of these two hypotheses by investigating temporal change in incisor morphology. Her results found no morphological trajectory from the Neandertal to the modern condition in Western Europe (with the caveat that data for Upper Paleolithic samples were unavailable). However, she felt that a better case for gradual evolution could be made for Central Europe. This is because she observed a trajectory of change from the incisor form observed in Neandertals to that observed in Upper Paleolithic (Dolní Věstonice) and recent Central Europeans.

A chart of the frequency of dental traits in Neanderthals. There’s more detailed information on the pdf

And another showing the mean distances between sampled groups..

Although the conclusion of this publication was that there was no evidence of significant interbreeding (which is probably correct) it doesn’t make a comment on lowlevels of interbreeding. This is probably because the low (5% or less) level suggested by a couple of DNA studies wouldn’t make a noticeable impact on the appearance of the UP European samples.

The affinity of the dental remains from Obi-Rakhmat Grotto

The affinity of the dental remains from Obi-Rakhmat Grotto, Uzbekistan

 9 July 2007Accepted 19 March 2008

A human partial maxillary dentition and a fragmentary cranium were recovered from Obi-Rakhmat Grotto in northeastern Uzbekistan in 2003. Initial descriptions of this single juvenile (OR-1) froma Middle Paleolithic archaeological context have emphasized its mosaic morphological pattern; the dentition appears archaic, while certain morphological aspects of the cranial fragments may be more ambiguous. The present study provides a systematic and comparative analysis of the dental morphology and morphometrics of OR-1 to provide a more refined appraisal of its phenetic affinity vis á vis Neandertals and modern humans. Two analyses were performed. The first uses 28 non-metric dental traits scored from Neandertals, Upper Paleolithic, and Middle Paleolithic modern humans to assess the posterior probability of group membership for the Obi-Rakhmat individual. The second is a morpho-metric analysis of the first upper molar of OR-1. The results of both analyses suggest the dentition of OR-1is essentially Neandertal.

 

Neanderthal brain size at birth provides insights into the evolution of human life history

Neanderthal brain size at birth provides insights into the evolution of human life history.

Ponce de León MS, Golovanova L, Doronichev V, Romanova G, Akazawa
T, Kondo O, Ishida H, Zollikofer CP.

Anthropological Institute and Museum, University of Zurich,

From birth to adulthood, the human brain expands by a factor of 3.3, compared with 2.5 in chimpanzees [DeSilva J and LesnikJ (2006) Chimpanzee neonatal brain size: Implications for brain growth in Homo erectus. J Hum Evol51: 207-212]. How the required extra amount of human brain growth is achieved and what its implications are for human life history and cognitive development are still a matter of debate. Likewise, because comparative fossil evidence is scarce, when and how the modern human pattern of brain growth arose during evolution is largely unknown. Virtual reconstructions of a Neanderthal neonate from Mezmaiskaya Cave (Russia) and of two Neanderthal infant skeletons from DederiyehCave (Syria) now provide new comparative insights: Neanderthal brain size at birth was similar to that in recent Homo sapiens and most likely subject to similar obstetric constraints. Neanderthal brain growth rates during early infancy were higher, however. This pattern of growth resulted in larger adult brain sizes but not in earlier completion of brain growth. Because large brains growing at high rates require large, late-maturing, mothers [Leigh SR and Blomquist GE (2007) in Campbell CJ et al. Primates in perspective; pp 396-407], it is likely that Neanderthal life history was similarly slow, or even slower-paced, than in recent H. sapiens.

I keep getting conflicting information on Neanderthal growth rates. One tooth study suggested it was the same as modern humans, another that it was faster. Now this suggests it was slower. I suspect it wasn’t a lot different.

Humans Wore ‘Shoes’ 30,000 Years Ago

Humans Wore ‘Shoes’ 30,000 Years Ago

Those high-tech, air-filled, light-as-a-feather sneakers on your feet are a far cry from the leather slabs our ancestors wore for protection and support.

But believe it or not, our modern day Nikes and Reeboks are direct descendents of the first supportive footwear that new research suggests came into use in western Eurasia between 26,000 and 30,000 years ago.

Erik Trinkaus, Ph.D., the Mary Tileston Hemenway Professor of Physical Anthropology, derived those dates by analyzing anatomical evidence of early modern humans, which suggests a reduction in the strength of the smaller toes in Upper Paleolithic humans while there was little change in leg strength.

His research was published in the July issue of the Journal of Archaeological Science.

Trinkaus argues that early humans living in far northern climates began to put insulation on their feet around 500,000 years ago. While archaeological evidence suggests that protective footwear was in use by at least the middle Upper Paleolithic in portions of Europe, the frequency of use and the actual mechanical protection provided by that footwear was unclear.

Use of protective footwear has been difficult to document because in most cases the footwear does not survive the test of time.

Lacking such physical evidence, Trinkaus analyzed the foot bones of western Eurasian Middle Paleolithic and middle Upper Paleolithic humans. In doing so, he found the anatomy of their feet began to change starting around 26,000 years ago.

“I discovered that the bones of the little toes of humans from that time frame were much less strongly built than those of their ancestors while their leg bones remained large and strong,” Trinkaus said. “The most logical cause would be the introduction of supportive footwear.”

During barefoot walking, the smaller toes flex for traction, keeping the toe bones strong. Supportive footwear lessens the roll of the little toes, thus weakening them.

Well, Neanderthals would have had to wear shoes really. Winter in Europe isn’t realy possible without boots. Did they sew them? I don’t recall seeing any evidence that they sewed. Maybe neanderthals just wrapped and tied their shoes on.

New Neanderthal reconstruction in New Scientist magazine

They are calling her Wilma, apparently.

And one of her naked with a spear; Britney Spears she isn’t.

Wouldn’t stand out in a crowd that much. Looks like my nan naked.