De Neanderthaler

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De Neanderthaler

Bericht  Grendel op do 05 feb 2009, 19:52

New Evidence Debunks 'Stupid' Neanderthal Myth

    Research by UK and American scientists has struck another blow to the
    theory that Neanderthals (Homo neanderthalensis) became extinct because
    they were less intelligent than our ancestors (Homo sapiens). The
    research team has shown that early stone tool technologies developed by
    our species, Homo sapiens, were no more efficient than those used by
    Neanderthals.


    Published in the Journal of Human Evolution, their discovery
    debunks a textbook belief held by archaeologists for more than 60
    years.


    The team from the University of Exeter, Southern Methodist
    University, Texas State University, and the Think Computer Corporation,
    spent three years flintknapping (producing stone tools). They recreated
    stone tools known as 'flakes,' which were wider tools originally used
    by both Neanderthals and Homo sapiens, and 'blades,' a narrower stone
    tool later adopted by Homo sapiens. Archaeologists often use the
    development of stone blades and their assumed efficiency as proof of
    Homo sapiens' superior intellect. To test this, the team analysed the
    data to compare the number of tools produced, how much cutting-edge was
    created, the efficiency in consuming raw material and how long tools
    lasted.


    Blades were first produced by Homo sapiens during their
    colonization of Europe from Africa approximately 40,000 years ago. This
    has traditionally been thought to be a dramatic technological advance,
    helping Homo sapiens out-compete, and eventually eradicate, their Stone
    Age cousins. Yet when the research team analysed their data there was
    no statistical difference between the efficiency of the two
    technologies. In fact, their findings showed that in some respects the
    flakes favoured by Neanderthals were more efficient than the blades
    adopted by Homo sapiens.


    The Neanderthals, believed to be a different species from Homo
    sapiens, evolved in Ice Age Europe, while the latter evolved in Africa
    before spreading out to the rest of the world around 50-40,000 years
    ago. Neanderthals are thought to have died out around 28,000 years ago,
    suggesting at least 10,000 years of overlap and possible interaction
    between the two species in Europe.


    Many long-held beliefs suggesting why the Neanderthals went extinct
    have been debunked in recent years. Research has already shown that
    Neanderthals were as good at hunting as Homo sapiens and had no clear
    disadvantage in their ability to communicate. Now, these latest
    findings add to the growing evidence that Neanderthals were no less
    intelligent than our ancestors.


    Metin Eren, an MA Experimental Archaeology student at the
    University of Exeter and lead author on the paper comments: "Our
    research disputes a major pillar holding up the long-held assumption
    that Homo sapiens were more advanced than Neanderthals. It is time for
    archaeologists to start searching for other reasons why Neanderthals
    became extinct while our ancestors survived. Technologically speaking,
    there is no clear advantage of one tool over the other. When we think
    of Neanderthals, we need to stop thinking in terms of 'stupid' or 'less
    advanced' and more in terms of 'different.'"


    Now that it is established that there is no technical advantage to
    blades, why did Homo sapiens adopt this technology during their
    colonization of Europe? The researchers suggest that the reason for
    this shift may be more cultural or symbolic. Eren explains: "Colonizing
    a continent isn't easy. Colonizing a continent during the Ice Age is
    even harder. So, for early Homo sapiens colonizing Ice Age Europe, a
    new shared and flashy-looking technology might serve as one form of
    social glue by which larger social networks were bonded. Thus, during
    hard times and resource droughts these larger social networks might act
    like a type of 'life insurance,' ensuring exchange and trade among
    members on the same 'team.'"


    The University of Exeter is the only university in the world to
    offer a degree course in Experimental Archaeology. This strand of
    archaeology focuses on understanding how people lived in the past by
    recreating their activities and replicating their technologies. Eren
    says: "It was only by spending three years in the lab learning how to
    physically make these tools that we were able to finally replicate them
    accurately enough to come up with our findings."


    This research was funded by the National Science Foundation of the USA and the Exeter Graduation Fund.


    Journal reference:


    1. Metin I. Eren, Aaron Greenspan, C. Garth Sampson. Are Upper
    Paleolithic blade cores more productive than Middle Paleolithic
    discoidal cores? A replication experiment. Journal of Human Evolution,
    Published online August 26, 2008

Bron: http://www.sciencedaily.com/releases/2008/08/080825203924.htm
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Re: De Neanderthaler

Bericht  Grendel op ma 09 feb 2009, 09:02


Neanderthal genome to be unveiled
Draft sequence opens window on human relatives.

Rex Dalton

The entire genome of a 38,000-year-old Neanderthal has been sequenced by a team of scientists in Germany. The group is already extracting DNA from other ancient Neanderthal bones and hopes that the genomes will allow an unprecedented comparison between modern humans and their closest evolutionary relative.

Helaas moet je betalen voor de rest van het artikel:

http://www.nature.com/news/2009/090204/full/457645a.html?s=news_rss

Wel nog een paar interessante reacties op deze pagina:

Neanderthal specimens characteristically display a thick, bowed shaft of the thigh bones, and a bowed femur. The interpretation is that these hominids were stronger and physically more robust than co-existing Homo sapiens-like hominids. But recall that marrow of the long bones, and of the pelvis harbors a large cache of hematopoietic stem cells (HSCs). The anatomy of the marrow, being soft tissue, is not preserved in the fossils. My speculation is that H. sapiens at the time had already evolved a more adaptable immune system than the Neanderthals, and had larger marrow spaces and less robust bones to match. The place to look genetically at this hypothesis is on the 30 MB interval on 6p which encodes HLA-A, C, B, DR, DQ, DP and the lympotoxin/TNF genes. The so-called "extended haplotypes" in this region show a suppression of crossing over, as if the entire unit tends to be inherited as a bloc. Although there will be some cool hints about the immune system at 14q32, where IgH is encoded (likely a significantly-reduced V, D, and J diversity), the HLA 6p region to me will be quite a surprise, providing hints for anthropologists on how modern humans can radiate so broadly in diverse biomes, coping with just about any new microbial challenge, in their rather rapid radiation across the globe.

In his book "The Ancestor's Tale" Richard Dawkins makes the comment that there is a chance that a given ancestor's DNA is not represented in your DNA, particularly if that ancestor's genes had not fit in with the rest of your genes. Which leads to the possibility that Neanderthalers could be in our ancestry without there being any Neaderthaler DNA left. I don't think it is likely, but who knows.
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Re: De Neanderthaler

Bericht  Grendel op wo 11 feb 2009, 20:37

Sibbevader schreef:Neanderthaler uit Scladina-grot geeft oudste DNA vrij



Wetenschappers hebben DNA van een 100.000 jaar oude Neanderthaler
kunnen bestuderen. Dit is het oudst gekende DNA van het menselijke type
tot nu toe. Het DNA werd geëxtraheerd uit de tand van een
Neanderthal-kind dat gevonden werd in Scladina, een Belgische grot in
de buurt van Luik. Dat staat te lezen in de nieuwste editie van het
vaktijdschrift Current Biology.



De studie beweert dat de Neanderthalers genetisch veel
verschillender dan dat we eerst dachten. De wetenschappers isoleerden
het mitochondriaal DNA en dit werd onderzocht. Het DNA bevatte 123
paren die werden ontcijferd en vergeleken met andere gekende
DNA-sequenties van Neanderthalers gedateerd tussen 29.000 en 42.000
jaar oud.



"De Scladina-sequentie toont aan dat de genetische diversiteit van
Neanderthalers altijd onderschat is geweest," aldus het team dat geleid
wordt door dr. Catherine Hanni van de Ecole Superieur van Lyon. "Dus er
is meer nodig dan de zes volledige sequenties om de genetische
diversiteit van de Neanderthalers volledig te kennen."



Deze studie toont aan dat de genetische diversiteit groter was in
vroegere tijden dan later wanneer de Homo sapiens zijn intrede doet in
Europa. Deze veranderingen zijn volgens onderzoekers een reflectie van
de fluctuaties van de bevolking, als gevolg van ziektes of de
verandering van de omgeving, alsook van de genetische mutaties die
hebben plaats gevonden in de loop der tijden.
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Re: De Neanderthaler

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