[Paleopsych] Archeology: The New Neandertal

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The New Neandertal
http://www.archaeology.org/0507/etc/letter.html

First, the summary from the "Magazine and Journal Reader" feature of the daily 
bulletin from the Chronicle of Higher Education, 5.8.17
http://chronicle.com/daily/2005/08/2005081701j.htm

    A glance at the July/August 2005 issue of Archaeology: A different
    sort of caveman

    New technology, combined with some very old fossils, is changing
    established theories about Neanderthals, writes Jean-Jacques Hublin,
    director of the department of human evolution at the Max Planck
    Institute for Evolutionary Anthropology, in Leipzig.

    With their heavy brows and robust bones, Neanderthals were originally
    viewed as "brutish cave dwellers" much different from today's human
    beings, says Mr. Hublin. As more research was performed, though,
    scientists began to see more similarities between the ancient species
    and Homo sapiens. Through the use of "virtual fossils," a "new"
    Neanderthal is emerging that is "both very similar to and very
    different from us," he says.

    "Virtual fossils" are digitally manipulated projections that allow
    researchers to imagine missing pieces from existing fossils. For
    example, if one side of a skull is damaged, its opposite side can be
    copied and reversed to create a complete, composite specimen. Using
    similar technology to examine Neanderthal teeth, researchers have
    learned that Neanderthals reached adulthood approximately three years
    sooner than people do today.

    Neanderthals and Homo sapiens seem especially similar when researchers
    consider how much the two differ from apes, says Mr. Hublin. DNA
    studies of Neanderthals and modern humans, for instance, reveal a
    limited genetic variation in both that contrasts strongly with the
    high variability common among African apes.

    A Neanderthal in a suit and tie would still stand out today, he
    writes, but "as the last branching of the human evolutionary tree and
    our closest relatives in the recent past, they will remain an object
    of popular fascination" and "scientific interest." Perhaps, though,
    "how we envision Neandertals may tell us as much about the way we see
    ourselves as about them," writes Mr. Hublin.

    The article, "The New Neandertal," is available online at
    http://www.archaeology.org/0507/etc/letter.html

    --Jason M. Breslow
      _________________________________________________________________

    departments
    Letter From New York: The New Neandertal Volume 58 Number 4,
    [4]July/August 2005
    by Jean-Jacques Hublin

    Virtual fossils and real molecules are changing how we view our
    enigmatic cousin.

    Next year will mark the 150th anniversary of the discovery at
    Neandertal, a little valley near Duesseldorf in western Germany, of
    the first recognized fossil humans. The occasion will be commemorated
    with conferences and exhibitions at major German museums. As a warm-up
    for this "Neandertal Year," two dozen scholars gathered at New York
    University this past January, in a Manhattan suffering near-glacial
    conditions, to exchange views on the latest advances in the field.

    Our fascination with Neandertals is well founded. They were the first
    known example of an extinct species of human, they evolved mostly in
    Europe, and we now have an unrivaled fossil record accumulated by a
    century and a half of research. Because there are more specimens of
    Neandertals than any other premodern human, any new techniques or
    approaches in paleoanthropology are usually applied to them first. And
    in recent years we have learned a great deal about these humans that
    once seemed unattainable, including aspects of their biology such as
    genetics. Studies have also revealed unexpected features of their
    growth, development, and life history. Even more traditional
    approaches, such as the comparison of Neandertal and modern human bone
    shapes, continue to yield new data.

    Visions of the Neandertals as brutish cave dwellers prevailed for many
    years following their discovery. The first reconstruction, in 1908,
    was based on the partial skeleton of an old male found at La Chappelle
    aux Saints in France, but the individual had been stooped from
    arthritis. That fact, and its projecting face, heavy brow, and
    generally robust bones gave rise to our earliest, though inaccurate,
    view of Neandertals. But in the last decades of the twentieth century,
    the pendulum began to swing in the opposite direction. For some,
    Neandertals appeared only as a slightly different population of our
    own species, adapted to the cooler climates of the Paleolithic world.
    The most politically correct version saw them as almost
    indistinguishable from modern humans in abilities and behaviors, and
    hardly differing in many anatomical aspects. The New York conference
    provided a more balanced picture of a "New Neandertal" that is both
    very similar to and very different from us.

    Emblematic of this New Neandertal is a composite skeleton created at
    the American Museum of Natural History in New York and discussed at
    the conference by Ian Tattersall, one of its curators. Most scholars
    have focused on analyzing particular parts of the skeleton, such as
    the skull or pelvis, so the reconstruction is our first look at an
    entire one. It is a large male, built from casts of bones from several
    individuals (most are from two finds, one at La Ferrassie, France, and
    the other at Kebara, Israel). Tattersall emphasized how different it
    is from our own skeletons, not only in the anatomy of the skull, which
    is well known, but in entire body shape. If any living Neandertals had
    come to the conference dressed in a suit and tie, they still would
    have stood out. But this composite skeleton was only one of many
    innovative approaches to finding the new Neandertal that were
    presented in New York.

    Virtual Fossils

    Human fossils are precious and fragile, and to study them scientists
    have embraced or developed new methods in recent years. CT scanning,
    for example, is used with increasing frequency to assess fine internal
    details of specimens, such as the inner ear of Neandertals. Imaging
    techniques, combined with sophisticated software for manipulating
    digitized fossils, allow us to work with virtual objects rather than
    the originals. One can now reconstruct fragmentary specimens, piecing
    them together on the computer and supplying missing parts. If a
    skull's right side is damaged, the left can be copied and a mirror
    image of it substituted instead. Even specimens warped and distorted
    in the fossilization process can be straightened out.

    The new methods of "virtual paleoanthropology" have been used to
    investigate how modern humans and Neandertals differ even in
    childhood. At the New York meeting, Marcia Ponce de Leon and Christoph
    Zollikofer of the University of Zurich presented a computer model and
    simulation comparing skull growth, showing the divergence of shape
    began early in development and reflected different growth patterns in
    the bones. Another comparison of Neandertal and modern human childhood
    development was recently undertaken by Fernando Ramirez-Rozzi of the
    French Centre National de la Recherche Scientifique in Paris and Jose
    Maria Bermudez de Castro of Madrid's Natural History Museum. They
    looked at tooth enamel, which has microscopic striations that can be
    counted like the growth rings in a tree trunk, and concluded that
    Neandertals reached adulthood at about 15 rather than 18 years of age,
    as in present-day human populations. Further analysis will confirm
    whether or not this was the case.

    Modern human specimens are also being digitized, allowing us to assess
    bone shape and size variations and understand their significance in
    anatomical evolution. In a remarkable contribution at the conference,
    Katerina Harvati and Tim Weaver of the Max Planck Institute for
    Evolutionary Anthropology in Leipzig, Germany, looked at skull
    variation in modern humans from different climates and cultures. They
    found that the shape of the face is linked to local environmental
    conditions, which fits well with the current belief that the
    Neandertal's projecting face is a cold-climate adaptation. By
    contrast, the shape of the brain case, particularly the temporal bone
    (on the side of the skull), proved to be a good indicator of genetic
    closeness among populations.

    Real Molecules

    Meanwhile, the genuine specimens have been the object of increased
    attention through the study of DNA, proteins, and chemical elements
    that can be found in bones and teeth--giving us a completely new
    source of valuable information about our remote relatives' biology and
    their daily lives.

    In 1997, a fragment of DNA was reconstructed from the same bones that
    the quarry workers found in Neandertal in 1856. The DNA of the
    Neandertal fell outside modern human variation, and suggested a
    divergence between the ancestors of Neandertals and modern humans
    nearly half a million years ago. Since the original DNA study, nine
    other Neandertal individuals have yielded some genetic information,
    all similar to one another yet distinct from that of modern humans.
    Although this number is small, the evidence gives us insight into the
    demography of the Neandertals. The limited variability of their DNA
    suggests that there were times, perhaps during glacial advances, when
    their population was greatly reduced, resulting in genetic
    bottlenecking. The population recovered in size afterward but with
    fewer surviving different genetic lines. In this respect,
    humans--modern, Neandertal, and others--strongly contrast with African
    apes, which evolved in a much less stressful environment during the
    last several hundred thousand years, and therefore have much greater
    genetic variability.

    Interestingly, while we can now study Neandertal DNA, it is very
    difficult to analyze DNA from the early modern humans who replaced
    them between 40,000 and 30,000 years ago. Because Neandertal DNA is
    different from our own, modern contamination (from excavators, museum
    curators, or laboratory personnel) can be identified and discounted.
    With fossils of our own forebears, however, differentiating ancient
    DNA from recent contamination is virtually impossible. Such research
    can only be undertaken with new fossil finds that are kept in sterile
    conditions from the field to the lab.

    There is no evidence that the last Neandertals were evolving toward a
    physical appearance like our own, but the issue of the possible
    contribution of Neandertals to the modern European genetic makeup is
    still fervently debated. Even if Neandertals represented a distinct,
    although very close, species separate from modern humans, we know that
    in nature, hybridization is a common process under such circumstances.
    At the conference, Trenton Holliday of Tulane University surveyed the
    zoological evidence, pointing out many hybrids among large mammals
    including members of the camel, horse, dog, and cat families. Did
    Neandertals and modern humans interbreed? It is quite possible in some
    instances, but it had no major biological results.

    Proteins can now be recovered from bones and examined with methods
    similar to those used with DNA. This year, for the first time,
    Christina Nielsen-Marsh of the Max Planck Institute was able to
    extract and analyze a protein from Neandertal teeth from Shanidar,
    Iraq. In Neandertals, this particular protein (osteocalcin) displays a
    sequence similar to that of modern humans, indicating it has changed
    little over a long period of time. In the near future, extraction and
    sequencing of fossil proteins may open new ways to study evolutionary
    relationships between extinct species, and may allow us to go farther
    back in time than is possible with ancient DNA, which is more complex
    and degrades more quickly.

    Scientists are investigating other molecules and chemical elements
    found in Neandertal bones. Collagen, routinely extracted from bone
    today for radiocarbon dating, yields carbon and nitrogen, while
    strontium and calcium can be sampled from the mineral parts of bone.
    These four elements can give us indications of an individual's diet,
    since they come from foods. Studies by Herve Bocherens of the Centre
    National de la Recherche Scientifique in Montpellier and Michael
    Richards of the Max Planck Institute suggest the European Neandertals
    were highly carnivorous, a pattern not unlike that observed in modern
    hunter-gatherers in cold regions. In the future, such analyses may
    also reveal indicators of population movements, since bone chemistry
    also reflects, for example, specific elements in ground water that
    vary from region to region.

    The Last Neandertals

    The possible interactions between Neandertals and modern invaders
    between 40,000 and 30,000 years ago in Europe remains one of
    paleoanthropology's most debated issues, so it was no surprise that it
    surfaced in New York. There is little doubt that the presence of
    another group of humans in Europe played a major role in the
    extinction of the Neandertals, through competition for resources if
    nothing else. But other factors in the Neandertals' demise have been
    discussed recently. For example, Chris Stringer of the Natural History
    Museum, London, has shown that this period was characterized by
    repeated and extreme climatic changes occurring in rapid succession.
    Although Neandertals had faced and survived severe climatic crises
    along the course of their evolution, the coincidence of this climatic
    instability with the invasion of the European territory by modern
    humans presented a double challenge for the last Neandertals. Both
    groups must have tried adapting during this confrontation in a very
    difficult environment. At the conference, Shara Bailey of the Max
    Planck Institute and I showed that Neandertals at the French cave site
    of Arcy-sur-Cure are indisputably associated with stone tools and bone
    ornaments formerly thought to have been made only by modern humans.
    The acquisition during this period of new techniques and habits, such
    as the use of body ornaments, by the last Neandertals is much debated
    by specialists. Many scholars believe it may have resulted from their
    encounters with modern humans, who had developed this behavior more
    than 100,000 years ago, even before leaving Africa. These contacts,
    they argue, may have been seldom, but resulted in imitation by the
    Neandertals or even trade between the two populations. But modern
    humans might have been affected as well. It has been proposed that the
    burst of artistic expression--cave art, figurines, and the
    like--observed in our forebears at this time relates to group
    identification and may have resulted from the interaction with these
    indeed human, but very different, beings.

    Because Neandertals are the best-known group of fossil humans, they
    are the group that always raises the most questions. As the last
    branching of the human evolutionary tree and our closest relatives in
    the recent past, they will remain an object of popular fascination as
    well as scientific interest. In fact, how we envision Neandertals may
    tell us as much about the way we see ourselves as about them. With the
    "New Neandertal" we have definitively shed two such images, one in
    which our ancient cousin was brutish and far different from us, the
    other in which we were nearly identical. But perhaps our new-found
    knowledge, from virtual fossils and molecular studies, is taking us to
    a deeper understanding of Neandertals.

    Jean-Jacques Hublin, director of the Department of Human Evolution at
    the Max Planck Institute in Leipzeig, has led fieldwork in France,
    Spain, and Morocco, and is now participating in an international
    project at Dikika, Ethiopia.