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The Well-Tailored Neanderthal; Or, They Walk Among Us!

They can get mitochondrial DNA (mtDNA) out of fossils to a certain age limit (I forget what) some Neanderthals are young enough for this, I think they have managed it with about 6 fossils so far...

It isn't possible to get Nuclear (genomic) DNA out of fossils that old, though. It's all to do with the size of the DNA and the number of copys in a cell - your average cell can easily have up to a hundred mitochondria, hence 100 copies of mtDNA, but theres only ever one nucleus. and mtDNA is much much smaller, so it's easier to find & sequence a certain bit of it...

I had a realy good article about all this, but I can't find the bastard anywhere and can't remember who it was by or anything...:(
I'll have a look over the weekend

going back to my last post, I just found out this morning that in fact, there has been a 'hybrid' fossil discovered quite recently - can't remember the details at the mo, and have to run, but I'll post more on that later...
 
Was that the child found (I think) in France? It caused quite a controversy. We should try to get an article or two linked to this thread.

What are you looking at me for? I'm busy.


looks busy
 
Was that the child found (I think) in France? It caused quite a controversy. We should try to get an article or two linked to this thread.

?
the one I was talking about is from Lugar Velho, in Portugal, might well be the one you'r thinkin of... it's a child (about 4 years old) and it's a fairly complete skeleton from about 24.5k years ago, that was found in a proper burial site and is covered in red ochre. The contoversy surrounding this one arises from the facts that it has a mosaic of human- and Neanderthal-like traits and the fact that before this, the latest date for Neanderthal remains is about 28k years ago. I've found an article here:
http://news.bbc.co.uk/1/hi/sci/tech/323657.stm
and another one here:
http://www.glenn.morton.btinternet.co.uk/hybrid.htm

The second one goes into a fair amount of detail, on this one and a couple of other skeletons, but seems to keep on throwing in creationist ideas:(

Ok, just found another one:
http://www.ox.ac.uk/gazette/1998-9/weekly/060599/news/story_5.htm

and heres a couple of hardcore journal articles, which I haven't had time to read yet, but look interesting:
http://www.pnas.org/cgi/content/full/96/13/7604
http://www.pnas.org/cgi/content/full/96/13/7117

I'm not sure if everyone will be able to get at these last two (being on university network has sooo many advantages;) )
If not let me know and I'll try and do a summary at some point...

anyway, I'm off down the pub. Cya Monday.
:_pished:
:smokin:
 
Relationship between Neanderthals and Homosapien sapien

I too took Anthropology many,many moons ago; and the thing that impressed me most was the impressive hunting skills the Neanderthals had. Their sense of smell was far superior to the Cromagnon's. They hunted in small packs and could communicate complex stratagies for tracking their prey. They made killing tools adequate to take down 2 ton mammals. They were sturdier and stronger than the "new comers" HSS. In fact I always suspected that the relationship HSS had with them was not too freindly. They may have even been the source of the "Boogy Man/Ogre" stories that Cromagnon Mothers used to keep their children closed to the cave at night! Beware the wolves with spears!!!!
 
Blow to Neanderthal breeding theory

Early humans and Neanderthals probably did not interbreed, according to evidence collected by Italian scientists.


Neanderthal man: Interbreeding debate continues
Scientists know that Neanderthals and early human ancestors were distinct species, even though they lived during the same period.

However, there is controversy over theories that Neanderthals made a contribution to the modern human gene pool.

A skeleton uncovered in Portugal appeared to show both Neanderthal and human features.

DNA taken

The latest research, from the University of Ferrara in Italy, compared genetic material from Neaderthals, Cro-Magnon humans and modern Europeans.

The DNA from the Neanderthals and Cro-Magnons was taken from their bones.

The DNA came from cell structures called mitochondriae rather than the nucleus.

They found that while, unsurprisingly, modern humans show clear genetic signs of their Cro-Magnon ancestry, no such link between Neanderthal DNA and modern European DNA could be established.

The results, they say, indicate that Neanderthals made little or no contribution to the genes of modern humans.

Out of Africa

The mitochondrial DNA of the two ancient species were very different, claims the study.

"This discontinuity is difficult to reconcile with the hypothesis that both Neanderthals and early anatomically modern humans contributed to the current European gene pool."

The finding supports the theory that the "anatomically modern human" arose in Africa some 150,000 years ago and dispersed, displacing the Neanderthals on the way.

It is a blow to the "multi-regional" theory, in which some interbreeding between Neanderthal and early humans is thought to have taken place.
BBC link
 
rynner said:

The skeletal evidence is pretty persuasive though that some traits did find their way into the mix. It's all pure conjecture but some human behavior is predictable.

Now, I'm going to relate a true story that in light of today's political correctness may be offensive to some-**so avert your eyes if you wish to remain unenlightened**
During WW2 my uncle was stationed in the Pacific, on his first shore leave he was offered to join a group of crewmates at one of the local brothels. He declined-(in his prejudiced world the natives seemed too "dark" to him) Upon hearing the excuse, one of the more experienced shipmates told him, and I quote, "Kid, the longer you're out here the lighter their skin will get!"

I feel that this scenerio has been played out millennia after millennia, where-ever groups of men traveling far from home have felt the need to seek out female "companionship".
I can almost hear the words spoken to a reluctant hunter in a frozen hostile and distant land, "Kid, the longer you're out here the smaller their browridges get".

Perhaps the children born from such liazons were sterile because the genetics were close but not a perfect match, like mules and Ligers.

Plus, for my part, there is a kind of wishful thinking that it would have been nice to have inherited Neanderthal bone density-practially ostioporosis proof!
 
What about Zana, the captured Russian "wild woman", who was said to have had Neanderthal-like characteristics (and to have possibly been a surviving Alma, the Russian "ape-man" cryptid thought by some to be surviving Neanderthals)? IIRC she had several children by human fathers (who, by the accounts I heard, drugged and raped her :() and one of her grandchildren is alive today. I read somewhere fairly recently that some researcher went to interview her grandson and found him to be much stronger than a "normal" man of his size and build should have been.

Last of the Neanderthals, or just a child with physical and mental abnormalities who was abandoned due to prejudice and grew up as a "feral human", like the recently found Nigerian "chimp boy"?
 
Zana

:) According to Dmitri Bayanov, who discusses Zana's story in one of his books (sorry, can't recall the title), after her last grandchild died, the Soviets fielded a team to search for Zana's grave. They weren't able to locate it, but they DID find the grandson's skull. Dmitri told me (last year) that they hadn't done any DNA studies on it yet. He didn't elaborate on the reasons for that, but considering Russia's severe financial straits, I can only presume they just don't have the proper lab facilities--or didn't at the time. It also appears they have no intention of handing it over to a western country to study. I'll have to remember to send Dmitri an e-mail and check on the current status of the skull. I'll let you know what he says, if anyone is interested. :)
 
Re: Zana

Originally posted by Wildlife I'll have to remember to send Dmitri an e-mail and check on the current status of the skull. I'll let you know what he says, if anyone is interested. :)

Oh, please! I'd be fascinated to know :D
 
http://news.bbc.co.uk/1/hi/sci/tech/3129654.stm

Fossils picked up in a Romanian bear cave are the oldest specimens yet found of modern humans in Europe, scientists say.

One of the items - a male, adult jawbone - has been dated to be between 34,000 and 36,000 years old.

The other pieces, which include the facial bone of an adolescent, are still being tested but are thought to be of a similar age.

This puts the fossils - from three different individuals - in a period in history when modern humans are believed to have shared the continent with Neanderthals, their now extinct hominid cousins.

Indeed, the researchers reporting the discoveries go so far as to suggest the fossils show some degree of hybridisation - they are possibly the result of interbreeding between modern humans and Neanderthals, they argue.

This is a position that drives a heated debate among scientists, many of whom doubt there was much mixing of the species.

These researchers point to DNA studies that indicate Neanderthals contributed little or nothing to the genes of humans living today.

Human development

The new finds, made in the Carpathian Mountains, are sure to prompt further argument.

They are detailed by Professor Erik Trinkaus and colleagues in two journals: the Proceedings of the National Academy of Sciences and the Journal of Human Evolution.

The team says the fossils, while undeniably modern (Homo sapiens), display some features that are very primitive in nature, such as large molars.

"Both the lower jawbone and the upper jaw of the face have the same pattern in the cheek teeth - the wisdom teeth in particular are simply huge. They are bigger than just about anything else we have from the last 200,000 years," Professor Trinkaus told BBC News Online.

"The best explanation I can put on it is that when modern humans spread out of Africa, they interbred with local populations of archaic humans, including the Neanderthals," said the Mary Tileston Hemenway Professor of Anthropology at Washington University in St Louis, US.

"It shows us that the earliest 'modern Europeans' were considerably less modern than we normally consider them to be, and that significant human evolution in details of anatomy has taken place since they became established across Eurasia."

'Wonderful mosaic'

The fossils were originally discovered in February 2002 in Pestera cu Oase - translated as the "Cave With Bones" - by three Romanian cavers.

It is not known how they got into the cave, but Professor Trinkaus says one possibility is that early humans used the site as a mortuary for the ritual disposal of human bodies.

The currently most popular model for the emergence of modern humans ties their origin to Africa within the last 200,000 years.

This theory argues that a wave of Homo sapiens then swept out across the world to replace all other human-like species, including Neanderthals.

Some molecular studies have seemed to refute any possibility that mixing took place - they indicate that our last common ancestor existed before Neanderthals themselves arose.

"The problem with this whole debate is that we have so few specimens in Europe - it's hard to make a hard and fast case," commented Professor Clive Gamble, from the UK's Centre of the Archaeology of Human Origins.

"The genetic studies are quite convincing but we need more information and that makes these new fossils very interesting. I'm sure that what we deal with eventually is going to be a more wonderful mosaic."

In June this year, another group of scientists reported the discovery of the oldest ever modern human remains at Herto in Ethiopia. The skulls were said to be about 160,000 years old.

The previous oldest modern human remains in Europe are dated to about 30,000 years ago.
 
The 'modern human' body plan was pretty much in place by the time of Homo erectus around 1.8 million years ago so the Neanderthals (either with or without the h is fine although it has to be Homo (sapiens?) neanderthalensis)

For a great resource see:

http://www.talkorigins.org/faqs/homs/

It deals with the Creationist interpretations of facts and tracks the news and important resources around.

I recommend the Trinkaus and Shipman book from the list:

http://www.talkorigins.org/faqs/homs/featuredbooks.html

Erik Trinkaus is possibly the leading expert on Neanderthals and he tends to have a rather Fortean viewpoint - he is sceptical of either theory of modern human origins (Continuity and Replacement) - some of his work comes down in favour of one viewpoint and some in favour of the other (he also publishes a lot in the PNAS and they make their older papers available online so hunt out some of them). The book deals with the history of the finds, the personalities and the changing theories and ideas and is an excellent study into how scientific theories change and develop over time.

Also don't be fooled by the media's coverage because the debate is still as lively as ever with Continuity proponents (like Milford Wolpoff and C. Loring Brace) still dealing out strong rebuffs to the morphological and genetic evidence.

Emps
 
(Thread moved to Earth Mysteries.)

Neanderthal hunters rivalled human skills
Neanderthals were not driven from northern Europe by vastly superior human hunters, suggests an analysis of hunting remains.

The study by Donald Grayson of the University of Washington and Francoise Delpech of the University of Bordeaux challenges a popular theory that the primitive peoples died out because they were far less skillful hunters.

The pair examined the fossilised remains of butchered animals from a cave in southwest France.

Neanderthals inhabited southern France from 65,000 years before the present until roughly 40,000 to 35,000 years ago. Neanderthals disappeared from the region about the time the earliest anatomically modern humans, known as Cro-Magnon appeared.

Precisely why Neanderthals disappeared remains a puzzle. But the idea that early humans were much more intelligent, dexterous and socially sophisticated is being questioned by a growing body of archaeological evidence.

Grayson and Delpech found no difference in the prey caught and butchered by Neanderthals and Cro-Magnon after studying more than 7200 bones and teeth from large hoofed animals.

Nimble-fingered

Both Neanderthals and Cro-Magnon feasted on a wide variety of ungulate species including reindeer, roe deer and horse. In both cases the proportion of different species consumed varied according to climatic changes.

"This study suggests Cro-Magnon were not superior in getting food from the landscape," says Grayson. "We could detect no difference in diet, the animals they were hunting and the way they were hunting across this period of time, aside from those caused by climate change."

Recent analysis of Neanderthal hand bones also shows that they were as nimble-fingered as early humans. Other archaeological evidence indicated that they may have been as intelligent and socially sophisticated as early humans.

Handheld spears

"Clearly they did pretty well for hundreds of thousands of years," says Chris Stringer, an archaeologist at the UK's Natural History Museum. "One has to assume they knew how to get meat when they needed it."

But Stringer adds that modern humans may have had better hunting technology, including harpoons, composite tools and possibly even fishing nets compared to the Neanderthals’ handheld spears.

Neanderthals also appear to have suffered more hunting injuries, he told New Scientist. These factors, combined with particularly difficult environmental conditions, may have given early humans a crucial edge.

"Being able to exploit the environment a little bit more efficiently could in the long run have led to the end of the Neanderthals," Stringer says.
 
*Bump*

The BBC again:

Late Neanderthals 'more like us'

By Paul Rincon
BBC News Online science staff




Neanderthals are thought to have been replaced by modern humans
Neanderthals were shedding their sturdy physique and evolving in the direction of modern humans just before they disappeared from the fossil record.
Newly identified remains from Vindija in Croatia, which date to between 42,000 and 28,000 years ago, are more delicate than "classic" Neanderthals.

One controversial explanation is that these Neanderthals were interbreeding with modern humans in the region.

Details of the research appear in the Journal of Human Evolution.

Excavations also reveal the Vindija Neanderthals were developing advanced ways of making stone tools that mirror innovations elsewhere by modern humans (Homo sapiens).

Researchers have pieced together a partial Neanderthal (Homo neanderthalensis) skull from fragments found mixed in with animal bones from the site.

Signs of interbreeding

The skull comes from ground layers dating to between 42,000 and 38,000 years ago. The researchers also found other fragments of Neanderthal bone from later ground layers in the cave.

Analysis of this cranium appears to confirm suggestions from earlier finds at Vindija that the Neanderthals there were evolving a more "gracile" anatomy - less sturdy than classic big-boned Neanderthals.


The partial skull has a high forehead and small brow ridges
The skull's supraorbital torus - an arching, bony ridge above the eyes - is not as thick and projecting as in other Neanderthal remains. The specimen also has a higher braincase than is typical in Neanderthals.

Co-author Ivor Jankovic, of the Institute for Anthropological Research in Zagreb, Croatia, told BBC News Online:

"You know, the Vindija material is interesting because it is more gracile than classic Neanderthals.

"It suggests some contact between Neanderthals and modern humans but we don't know yet whether there was some interbreeding."

Fierce debate

The suggestion that Neanderthals interbred with modern humans is highly controversial. Many researchers believe they did not contribute genes to present-day populations.

Most researchers now believe that our own species evolved in Africa and then swept across Europe, replacing the Neanderthals - the so-called "Out of Africa" model.

They were evolving in the same way because they were part of a larger human species

Dr James Ahern, University of Wyoming
Comparisons of mitochondrial DNA from Neanderthals and modern humans have failed to reveal any signs of mixing between the two populations.

But Dr James Ahern of the University of Wyoming, US, lead scientist in the latest study, thinks the replacement of Neanderthals by modern humans was not a simple process.

"There was a far more complex dynamic going on between 20,000 and 29,000 years ago than some people think.

"I'm sure that there were some things post-Neanderthal populations assimilated from their predecessors, certainly in the biological sense," Dr Ahern told BBC News Online.

Remains of early modern humans from Central Europe often display Neanderthal traits, say the researchers. But these features are no longer as common in present-day European populations.

Neanderthals began to evolve in Europe around 230,000 years ago and dominated the continent until around 35,000 years ago when people with a more modern anatomy entered the continent.

They were proficient hunters and well-adapted to an Ice Age climate. But their distinctive anatomy has led researchers to classify them as a separate species from us.

The Vindija cranium predates the first recorded presence of modern humans in Europe by around 5,000 years.

Common direction

Dr Ahern thinks this suggests that Neanderthals and modern humans in Africa were evolving in the same direction in response to common environmental pressures.

"They were evolving in the same way because they were part of a larger human species. Neanderthals just didn't change as rapidly as some of the other people," he explained.


"Classic" Neanderthals had robust features
These pressures may have been rooted in sharp changes in the global climate.

The evolution of a modern, or slight, physique by humans in Africa is thought to coincide with an emphasis on cultural and technological ways of dealing with everyday tasks that earlier people - including the Neanderthals - solved with brute force.

Innovations believed to coincide with the appearance of modern human anatomy include hunting with bows and arrows and the use of harpoons for fishing.

Dr Ivor Karavanic of the University of Zagreb found that around 38,000 years ago, Neanderthals began making more use of the mineral chert for stone tools.

Chert is a superior material to the quartz that Neanderthals at the site had previously used.

This behaviour mirrors cultural changes taking place at the same time in modern human populations and may indicate more advanced thinking



Original Story
 
I can never understand how the old cliche of the Neandertal on the subway would work. Their faces are very distinctive...

(I was told by a museum curator that modern humans `do` sometimes have brow ridges, but they are an exclusivy male trait.)
 
Homo Aves said:
I can never understand how the old cliche of the Neandertal on the subway would work. Their faces are very distinctive...

(I was told by a museum curator that modern humans `do` sometimes have brow ridges, but they are an exclusivy male trait.)

Neanderthals and modern humans although on their own evolutionary trajectories were following the general trend towards less robust cranial structure so when robust modern humans enter Europe with late Neadnerthals then there would have been some similarities (pos. due to diet - the postcranial skeleton suggests a different lifestyle with modern humans far more mobile). Vindija is a good example of one of these late sites but all the (many) finds have been pretty fragmentary, due to the site being a cave bear nest, which, along with some cryoturbation has mixed some levels (in some areas). Still interesting nonetheless - esp. as the very last Neanderthals (in Spain still using Middle Palaeolithic tools and dating to 10-15 thousand years later than Vindija) are still as robust as some of the classic Neadnerthals.

There are some modern humans with good brow ridges (pos influenced by activity and diet) - the only redeeming feature of Speed (apart from Dennis Hopper I suppose) is the brow ridges on th original bus driver).

Hypothesing a Neanderthal on the subway was always a bit silly - you could have probably done the same with Homo erectus (although clearly this would have been more unusual when it was first said - you'd have to look pretty outlandish to get much attention these days).

Emps
 
Were Neanderthals a species apart?

Skulls indicate they didn't interbreed with humans

Researchers compared the skulls of modern and ancient humans with those of Neanderthals, as well as 11 existing species of nonhuman primates including chimpanzees, gorillas and baboons. Their conclusion: Humans are as different from Neanderthals as they are from gorillas.

• Your guide to the planet's history

The Associated Press
Updated: 11:19 a.m. ET Jan. 27, 2004


WASHINGTON - A study of the skulls of Neanderthals, comparing them with early and modern humans, concludes that that ancient group is unlikely to have been the ancestor of people today.

Scientists have long debated whether modern people are related to Neanderthals, the squat, powerful hunters who dominated Europe for 100,000 years before dying out on the arrival of modern humans.

The new study, led by anthropologist Katerina Harvati of New York University, measured 15 standard landmarks on the face and skull of Neanderthals, early modern humans, current humans as well as other primate species.

The study, published this week in the Proceedings of the National Academy of Sciences, found that the differences measured between humans and Neanderthals were significantly greater than those found between subspecies of any single group. That finding supported the view that Neanderthals were not a subspecies of humans. In addition, the difference was as great or greater than that found between closely related primate species, such as humans, gorillas and chimpanzees.

While Harvati says the analysis “cannot completely rule out” a relationship between humans and Neanderthals, it strongly suggests they are separate species.

The dawn of humanity
Her report comes just four months after anthropologist Erik Trinkaus of Washington University in St. Louis reported the discovery of a jawbone in a cave in Romania that may be evidence of the earliest modern humans in Europe.

The jawbone, dated at 34,000 to 36,000 years ago when humans overlapped with Neanderthals, has characteristics similar to other early modern humans, but also certain features that indicate a possible Neanderthal connection, the researchers said. That suggests the possibility of interbreeding with Neanderthals.

Last March, Richard G. Klein of Stanford University, reported that while studies of DNA indicate that Neanderthals and humans had a common ancestor, there is no evidence that the two ever mixed in substantial numbers, which means that when the Neanderthals died out, so did their genes.

Vestiges of extinct branches?
But a study published in 2002 suggested that the genes of people today carry vestiges of genes of Neanderthals and other extinct branches of the human family.

That report by population biologist Alan R. Templeton of Washington University in St. Louis suggests there were at least two distinct human migrations out of Africa, the first between 420,000 and 840,000 years ago and the second between 80,000 and 150,000 years ago.

According to Templeton, the most recent migration, and perhaps both, were not “replacement events.” Rather, he said, DNA evidence shows evidence of interbreeding.

© 2004 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

http://www.msnbc.msn.com/id/4063766/

The human origins debate is great - its more like a game of ping pong than anything - Replacemnt fire a ball over the net Contuinity bang one straight back!!

Templeton has done a lot of work examining the claims for Replacement based on DNA - thats some interesting set of results - his first date range covers the appearance of H. heidelbergensis and the penetration fo the Acheulean into Europe.

Emps
 
Fossilised faeces

Mon 16 Feb 2004

1:34am (UK)

Prehistoric Poo Clue to Evolution

By John von Radowitz, Science Correspondent, PA News, in Seattle


Prehistoric poo could help scientists solve some of the greatest mysteries of early human evolution, it was revealed today.

Researchers are extracting DNA from fossilised faeces in the search for clues about the origin of language and the fate of the Neanderthals.

The coprolites are being dug up from the floor of caves in Israel, along with sediment containing ancient DNA from people and animals.

Traces of both Cromagnons, a race of early modern humans, and Neanderthals have been found in the caves at Mount Carmel near Haifa.

Neanderthals, which became extinct about 40,000 years ago, were not the ancestors of modern humans, but for a time they co-existed alongside our forbears.

Some scientists believe they may have interbred, and contributed to the genetic make-up of people living today. Others insist they kept apart and lived far from harmonious lives – perhaps even practising cannibalism.

By examining the coprolites and sediment samples scientists hope to see if any Cromagnon DNA contains Neanderthal sequences. If so, it would suggest that interbreeding took place.

Coprolite DNA might also provide evidence of cannibalism.

Dr Hendrik Poinar, from McMaster University in Hamilton, Ontario, who is leading the research, said: “In theory from the coprolite you’re going to find the DNA of the defecator and the DNA of the consumer. Unfortunately in that kind of case it’s very difficult to determine who ate who.”

Another key goal is to search for clues about the origin of language, Dr Poinar said at the American Association for the Advancement of Science’s annual meeting, in Seattle.

No-one knows if Neanderthals were able to communicate with words, or whether language only evolved with the arrival of early modern humans.

Dr Poinar plans to search for a particular gene linked to muscular development associated with language and see if it had been selected for in Neanderthal evolution .

“Did the Neanderthals know how to speak?” said Dr Poinar. “I find that aspect fascinating.”

http://news.scotsman.com/latest.cfm?id=2536167

I wonder if he is going to try and combine the research with the recent dog DNA results and see if they ever shouted for someone to go and fetch them more leaves as the Andrex wolf stole the last sheet ;)

Emps
 
Primate inter-breeding

http://www.nature.com/nsu/040315/040315-4.html

This story on FT breaking news today, about lack of genetic evidence for neanderthal/homo sapiens inter-breeding, includes one sentence that puzzled me:

Chris Stringer, of the Natural History Museum, says that:

"The two groups were closer in genetic terms than other primates that happily breed today".

What does this mean - Gorilla/orang utan hybrids? Gibbon/chimpanzee crosses? Stringer seems to imply that this happens? Anybody able to shed any further light? Or is he just talking about interbreeding between sub-species of chimp etc.?
 
I'd need to look through my books at hom but there a number of primates that interbreed - it is often stated that some monkey species look very similar but aren't interfertile and some that look physcially different that can interbreed. I'm not aware of any great ape hybrids but they are different genus not just species. I assume they are probably refering to monkeys were there are lots of species an subspecies in close proximity. Stringer's stance is that we are H. sapiens and they are H. neanderthalensis i..e spearte at the species level and not interfertile (which would be the implied case if we had to reclassify the two groups into H. sapiens sapiens and H. sapiens neanderthalensis).

Emps
 
Cheers - thanks for clearing this up.

I realise now I read "ape" where he clearly says "primate".
 
Maybe we should also consider that modern humans and neandertals may not have interbred because their sexual strategies may have been different.

Many female primates , not least the great apes, exhibit distinct signs of estrus either by obvious physical changes or behavioral changes or both. Humans don't exhibit that pattern. Human females themselves don't even know when they are fertile, much less the males. And human females tend to be sexually receptive all the time, not just during their fertile periods.

So, what if neandertals showed the common primate pattern of obvious signs of sexual receptivity and fertility? As humans don't, and probably didn't even during the period that they shared the world with their neandertal kin, the likelihood of them interbreeding would be markedly reduced, even if there was a theoretical possibility of them producing live young.

The neandertals were isolated in Europe for many tens of thousands of years before they came into contact with anatomically modern humans. There was plenty of time for speciation to occur while they were so isolated. And, as reproductive behavior doesn't fossilise, we can't be sure that they carried modern humanity's rather odd (in primate terms) pattern of reproductive behavior. We can't even be sure how long humans have behaved that way.
 
You've never heard of PMS then, Sebastian? ;)

Sorry, but I suspect that it's cultural conditioning rather than genetics that makes human females (and males) unsure of their fertility. Speaking personally, the sex drive does go up and down depending on the "time of the month".

Jane.
 
Sebastian: I suspect concelead estrus developed with the emergence of bipedalism and there has been a lot of (potenitally controversial) work on the use of ochre and the "sex strike theory". Chris Knight of the University of East London has lead the research in this area. See Taylor's "The Prehstory of Sex" for an overview.

It is more likely that if they weren't interfertile then it was somehting more fundamental like incompatibility of the sperm and eggs - small changes in enzymes, etc. could lead to reproductive barriers.

Emps
 
It's certainly a major problem that good samples of neandertal nuclear DNA aren't available for analysis. Now that both human and chimpanzee DNA has been sequenced, a neandertal sample would be very illuminating to say the least.

Still, I think that the hypothesis that humans and neandertals were distinct species whose reproductive strategies were different remains a good one, even if it's only based on little more than speculation. I'll have to look up Chris Knight's views and also Taylor's "Prehistory of Sex"; thanks for the tip-off Emperor.

I'm not sure, Jane, that I totally agree with your view that human blindness toward the relatively small window of opportunity for conception is largely culturally based. Although, obviously unlike you, I can't speak from personal experience on cycles in women's sexual receptivity, I can at least comment from observation on the other side of the equation. It seems that some women are often most receptive at those times when they would be least fertile. Still, there must have been research carried out somewhere on such an important issue. Does anyone know of it?

Wouldn't it be cool if there was a neandertal corpse lying under a glacier somewhere, all nicely preserved like Otzi? Still, maybe that's too much to hope for. One 5000 year old body was miraculous enough; a 30,000 year old one would be completely out of the question. :(
 
An interesting insight in human origins research - whenever a study comes out supporting Replacement (i.e. the complete or partial replacement of other hominds by spreading modern humans) someone from the opposing, Continuity (i.e. modern humans evolved largely from the flow of genes between different groups of hominds in different areas), camp pops up pointing at potential problems (its usually either Milford Wolpoff or the geneticist Alan Templeton):

Did Neanderthals and humans mix?

By STEPHEN STRAUSS
Saturday, April 3, 2004 - Page F10


One of the abiding questions in human evolution is the intimacy of the relationship between early people and their clear, near relations, the Neanderthals.

At one time, it was hoped that a genetic study of ancient DNA would tell us definitely whether a Neanderthal was our uncle 10,000 times removed, but a recent analysis of the remains of the two species have demonstrated just how difficult that is, and may always be.

When DNA taken from the bones of early humans was compared with DNA taken from Neanderthals who lived in roughly the same time period, no trace of Neanderthal genetic material was found sloshing about in any early Homo sapiens. On its face, this would suggest that the promiscuous mating some anthropologists have argued characterized early human and Neanderthal interaction never happened.

"There is no evidence to date that Neanderthals contributed to our current gene pool," says Svante Paabo, a geneticist with the Max Planck Institute for Evolutionary Biology in Germany and co-author of the study, which appeared in the Internet journal PLoS Biology.

This is in sharp distinction to the views of University of Michigan anthropologist Milford Wolpoff, who has argued that "so-called modern humans are a 50-50 combination of ancestry from both peoples," and to the position of University of Pennsylvania anthropologist Erik Trinkaus, who several years ago suggested the bones of a 25,000-year-old fossil of a boy found in Portugal indicated he was of mixed human and Neanderthal origin.

But this is less a contradiction than you might think.

Despite a paper entitled "No Neanderthal DNA contribution to early modern humans," the European scientists say there is also a highly negative way to interpret their data. "With our current DNA analysis techniques, we won't be able to resolve this issue and there is nothing we can do about that today," Prof. Paabo says.

Part of the difficulty is the way that modern human DNA now pollutes all sites of anthropological interest. "Human DNA is pervasive in paleontological and archeological remains as well as most laboratory environments. It is therefore currently impossible to differentiate contaminating modern DNA sequences from [native] DNA sequences in human remains," the paper's European authors write.

Simply translated, almost any sample of anything that you looked at would contain modern human DNA. To prove their point, the paper's authors extracted DNA from six cave beer teeth excavated from early human and Neanderthal sites. When standard DNA amplification technology, which is used to multiply the few remain bits of DNA found in ancient bones and teeth, was applied, human DNA was found. Naively interpreted, this would imply that bears and humans once mated.

The paper points out that this confusion is possible because the amplification techniques are so powerful that even a single molecule of DNA is enough to give a false reading to an entire sample. The contamination issue means that you can't look to see if Neanderthals carried any human DNA, but only -- as in the PLoS paper -- if the fossil remains of early humans contained any Neanderthal DNA.

A second difficulty is finding enough DNA to study. To publish its paper, the European group initially looked at 24 Neanderthals and 40 early modern human fossils. However, only four Neanderthals and five humans were judged to be well enough preserved to justify trying to extract DNA.

But the biggest caveat is the very special sort of DNA, so-called mitochondrial DNA, which scientists are forced to use in their research. It degrades less easily than the DNA in the cell nucleus and therefore can be retrieved from ancient fossils. Unfortunately, it is passed on only in women's eggs. This creates huge dead ends in every generation: If a woman had only sons, or only her sons survived long enough to reproduce, none of that family's DNA gets passed on in the species mitochondrial record.

As a consequence, it has been estimated that the more than six billion modern humans alive today may all carry mitochondrial DNA that can be traced back to only two to seven women who lived in the past.

Thus, Prof. Paabo says, a finding of zero Neanderthal mitochondrial DNA in the newly analyzed samples may simply indicate that what was there faded away in the 30,000 or so years since Neanderthals went extinct.

How big a contribution could Neaderthals have made to the human genetic makeup that would still be consistent with the findings of the new paper? "Not more than 25 per cent," Prof. Paabo responds.

Source

edit: refernce:

Serre,D. André Langaney, Mario Chech, Maria Teschler-Nicola, Maja Paunovic, Philippe Mennecier, Michael Hofreiter, Göran Possnert and Svante Pääbo (2004) No Evidence of Neandertal mtDNA Contribution to Early Modern Humans. PLoS Biology. 2 (3).313 - .7. ]
 
Neanderthals sped through puberty

Patricia Reaney
Thursday, 29 April 2004



Neanderthals reached adulthood as early as 15, say a pair of European experts after looking at tiny ridges on fossilised teeth.

The findings, reported today in the journal Nature, suggest the hominids matured at least three years before early modern humans.

The scientists say Neanderthals probably ate a high-calorie diet and a fast metabolism to fuel this rapid growth.

"Neanderthals, despite having a large brain, were characterised by a short period of development," said lead researcher Fernando Ramirez Rozzi, from the French research institute CNRS in Paris.

Creatures with large brains tend to have a lengthier growth period and take longer to mature, but Ramirez Rozzi with José Maria Bermudez de Castro, from Spain's National Museum of Natural Sciences in Madrid, found the opposite with Neanderthals.

"Until now the idea was: the longer the growth, the bigger the brain but in Neanderthals this relationship is completely broken," Ramirez Rozzi said.

"This difference in growth between Neanderthals and modern humans is, I think, very strong proof of two different species," he said.

Why they developed so quickly is a puzzle but Ramirez Rossi suspects Neanderthals had a high mortality rate because of the hostile conditions in which they lived and they adapted to this by maturing quickly.

Dental growth and maturity

The researchers studied the series of minute horizontal ridges, called perikymata, on fossils of front teeth.

The ridges are enamel that is routinely deposited on outer surface of the teeth as the creature proceeds through life. So, like tree rings, these give an indicator of maturation and mortality.

In the fast growth spurts of childhood, the ridges are close together; in adulthood, they start to spread out; and the gaps widen as old age progresses.

They compared teeth fossils from Neanderthals dating from 130,000 to 28,000 years ago, earlier samples dating between 800,000 and 400,000 years and teeth fossils of Homo sapiens that were 20,000 to 8000 years old.

"Neanderthals were characterised by having the shortest period of dental growth," said Ramirez Rozzi.

The scientists said this suggested that far from being a subsistence survivor, Neanderthals flourished in the environmental conditions and food availability at the time to fuel this fast growth.

But, if the teeth are any guide, they presumably paid for that with a short lifespan.

Jay Kelley, of the University of Illinois in Chicago, said in a commentary in the journal that more studies on teeth fossils were needed to support the researchers' conclusions.

"Nonetheless, these authors have opened up what should prove to be a fruitful line of research into both the relationships and the palaeobiology of Neanderthals," Kelley said.

http://www.abc.net.au/science/news/stories/s1097282.htm

Scientists say Neanderthals grew up faster than we do

Tooth analysis hints at adulthood by age 15

The black lines indicate perikymata, characteristic ridges on teeth that are caused by periodic changes in enamel growth. The ridges are less densely packed in Neanderthal fossil teeth, indicating that the species had a shorter period of dental growth and therefore matured more quickly than modern humans, researchers say.

The Associated Press
Updated: 01:01 PM PT April28, 2004

If you think your kids grow up fast, consider this: A new study suggests that Neanderthal children blazed through adolescence and on average reached adulthood at age 15.

The finding bolsters the view that Neanderthals were a unique species separate from modern humans, because the time for humans to mature to adulthood grew longer over the course of their evolution, said paleontologist Fernando V. Ramirez Rozzi, who led the study.

Rozzi, with the National Center for Scientific Research in Paris, based his study on analysis of Neanderthal teeth. It will be published in Thursday’s issue of the journal Nature.

If Neanderthals and prehistoric Europeans could be seen side by side 35,000 years ago, “the Neanderthals would be bigger,” Rozzi said. ”Probably human children of about 5 years old would play with Neanderthals that were 3 years old.”

“It’s a very exciting paper,” said anthropologist Katerina Harvati of New York University. “Our current understanding of Neanderthals is that they’re brutish and stupid, even though it turns out they have larger brains on average than ourselves.

“Now, this work actually supports the idea that ... they were dealing with the world in fundamentally different ways.”

A breed apart?
For more than 100,000 years, Neanderthals roamed across a vast region from Spain to southern Russia and western Asia, overlapping with anatomically modern man for several thousand years. Scientists disagree about how much interbreeding occurred between the groups and whether Neanderthals passed on any of their traits before they vanished some 30,000 years ago.

Harvati said their quick maturation rate may have been an adaptation to a harsh environment that decreased their life span and made it important for youngsters to reach sexual maturity quickly.

For his study, Rozzi spent about 18 months examining growth patterns on the crowns of incisors and canines from 55 individual Neanderthals, comparing them with corresponding patterns from early modern humans and ancestors to both groups. Like rings on a tree, the time it takes for a tooth to grow can be measured by counting visible lines that form about every nine days on the enamel.

On average, Rozzi found Neanderthals developed teeth 15 percent faster than modern humans. Therefore, a Neanderthal’s physical development, which mirrors tooth growth, must have been faster as well, he said.

Skepticism voiced
Erik Trinkaus of Washington University in St. Louis said he’s skeptical of the research. Human growth varies widely within a population, he said. In fact, Rozzi’s study includes some Neanderthal teeth that took as long to develop as modern human teeth.

University of Illinois at Chicago anatomy professor Jay Kelley said he’s also concerned about making conclusions based on what are essentially assumptions about Neanderthal tooth growth.

“That’s a little dicey,” said Kelley, who wrote an accompanying article in Nature calling for more research on the subject.

http://msnbc.msn.com/id/4855079/

Emps
 
The grandmother hypothesis

Old Age Was Secret of Modern Humans' Success



Humans began to live long and prosper only about 30,000 years ago, researchers report. Results published online this week by the Proceedings of the National Academy of Sciences reveal a striking increase in human longevity during the Upper Paleolithic Period when the number of people surviving to old age increased four-fold.

Rachel Caspari of the University of Michigan and Sang-Hee Lee of the University of California at Riverside, examined 768 hominid dental samples from a variety of locations and time periods. Included in the selection were fossils from Australopithecus, Homo erectus, and Neandertals from Europe and Western Asia. The researchers analyzed the amount of wear on the molars to determine the age of the individuals and defined as “old” those who reached double the age of reproductive maturation. A comparison of the number of old and young individuals in each time period revealed a dramatic increase in life span that occurred about 30,000 years ago. (The above photograph shows the skull of an early modern human from the site of Cro-Magnon in France.) “Significant longevity came late in human evolution and its advantages must have compensated somehow for the disabilities and diseases of older age, when gene expressions uncommon in younger adults become more frequent,” the scientists write.

The findings support the so-called grandmother hypothesis, which posits that older women no longer responsible for their own children help support the group by strengthening social bonds and providing greater opportunities to pass on specialized knowledge. "There has been a lot of speculation about what gave modern humans their evolutionary advantage,” Caspari remarks. “This research provides a simple explanation for which there is now concrete evidence: modern humans were older and wiser.”

http://www.sciam.com/article.cfm?chanID=sa003&articleID=00014256-090D-10EB-890D83414B7F0102

Emps
 
Its not exactly a new theory - Templeton has been publishing for years and the general Continuity Model of modern human origins is as old as any other.

New twist on out-of-Africa theory

Judy Skatssoon
ABC Science Online

Wednesday, 14 July 2004




Homo erectus, the species thought to be the first to leave Africa for Eurasia in the out-of-Africa model of human origin (Image: Science)

Early humans made love, not war, according to new DNA analysis presented at a genetics conference that gives a new twist on the out-of-Africa hypothesis of human origins.

U.S. researcher Professor Alan Templeton of Washington University, St Louis, debunks the prevailing version of the out-of-Africa hypothesis, which says early humans migrated from Africa and wiped out Eurasian populations.

Instead, they bred, he told the Genetics Society of Australia's annual conference in Melbourne this week.

Templeton said his evidence didn't support the so-called replacement theory in which African hominids caused the extinction of other Homo species.

Instead, he said his analysis of the human genome showed prehistoric gene-swapping created a single evolutionary lineage beginning in Africa and ending where we are today.

He looked at mitochondrial DNA, as well as DNA on a range of chromosomes including X and Y.

"The genetic legacy of current humans is predominantly of African origin," he said.

Templeton is the first to suggest expansion out of Africa occurred in three waves: 2 million years ago, 800,000 years ago and 100,000 years ago.

The alternative view suggests that expansion out of Africa occurred twice and caused the genetic extinction of existing populations, with the colonisers later diversifying into separate races.

What about races?

But Templeton said this extinction never happened and a combination of movement and interbreeding meant diversification of races didn't occur.

"We really have to abandon the idea of race. It actually does not reflect the genetic differences we can now measure in an objective fashion."

Templeton said the differences between human populations today were based on geography not genetics.

This meant a Norwegian would be more closely related than a Fijian to someone from sub-Saharan Africa.

"We do see differences in different regions of the world but the best indicator of those differences is simply geographical distance and not things like skin colour."

Templeton said his data was inconclusive on whether interbreeding also occurred with Neanderthals.

But he said there was fossil evidence that this probably occurred, which would imply a bit of Neanderthal could live on in us all.

Australian geneticist Associate Professor Philip Batterham from the University of Melbourne said the research showed humanity was far more closely related that previously thought and that race was a cultural phenomenon.

Templeton's research was published in the journal Nature in March 2002.

http://www.abc.net.au/science/news/stories/s1153697.htm
 
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