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terça-feira, 18 de dezembro de 2007
sexta-feira, 14 de dezembro de 2007
Afinal talvez falassem... meio caminho andado para o "namoro"
The Derived FOXP2 Variant of Modern
Humans Was Shared with Neandertals
Summary
Although many animals communicate vocally, no extant
creature rivalsmodernhumansin language ability.
Therefore, knowing when and under what evolutionary
pressures our capacity for language evolved is of great
interest. Here, we find that our closest extinct relatives,
the Neandertals, share with modern humans two
evolutionary changes in FOXP2, a gene that has been
implicated in the development of speech and language.
Wefurthermorefindthat in Neandertals, these changes
lie on the common modern human haplotype, which
previously was shown to have been subject to a selective
sweep. These results suggest that these genetic
changes and the selective sweep predate the common
ancestor (which existed about 300,000–400,000 years
ago) of modern human and Neandertal populations.
This is in contrast to more recent age estimates of the
selective sweep based on extant human diversity data.
Thus, these results illustrate the usefulness of retrieving
direct genetic information from ancient remains for
understanding recent human evolution.
http://www.anthro.utah.edu/PDFs/foxp2-neanderthals.pdf
Humans Was Shared with Neandertals
Summary
Although many animals communicate vocally, no extant
creature rivalsmodernhumansin language ability.
Therefore, knowing when and under what evolutionary
pressures our capacity for language evolved is of great
interest. Here, we find that our closest extinct relatives,
the Neandertals, share with modern humans two
evolutionary changes in FOXP2, a gene that has been
implicated in the development of speech and language.
Wefurthermorefindthat in Neandertals, these changes
lie on the common modern human haplotype, which
previously was shown to have been subject to a selective
sweep. These results suggest that these genetic
changes and the selective sweep predate the common
ancestor (which existed about 300,000–400,000 years
ago) of modern human and Neandertal populations.
This is in contrast to more recent age estimates of the
selective sweep based on extant human diversity data.
Thus, these results illustrate the usefulness of retrieving
direct genetic information from ancient remains for
understanding recent human evolution.
http://www.anthro.utah.edu/PDFs/foxp2-neanderthals.pdf
MAX PLANCK SOCIETY
Press Release
News / B / 2007 162)
Red hair and freckles ...
Genetic studies show that some Neanderthals may have had red or fair hair
and lighter coloured skin
Fossil remains of Neanderthals paint an incomplete picture; they cannot tell
us about their cognitive skills or give us details of what they looked like. Since
scientists in Svante Pääbo's team at the Max Planck Institute for
Evolutionary Anthropology in Leipzig started looking into the DNA of
Neanderthals, they have made some new and astonishing discoveries. Just
last week, the Leipzig scientists published their discovery of the human
variant of the FOXP2 gene in our nearest relatives. And they have now
revealed another interesting detail: at least one percent of the Neanderthals
in Europe may have had red hair, according to a report by researchers
working with Carles Lalueza-Fox at the University of Barcelona, Holger
Römpler at the University of Leipzig and Michael Hofreiter at the Max
Planck Institute in Leipzig in the online edition of Science (Science Express,
October 25, 2007).
Fig.: Red-haired Neanderthals and modern man face to face.
Image: Knut Finstermeier, Max Planck Institute for Evolutionary Anthropology;
original Neanderthal reconstruction: Reiss Engelhorn Museums, Mannheim
October 26th, 2007
A fashion magazine recently asked what hair colours were in this year, prophesizing an exceptionally large
number of red-haired men and women on the streets. In view of "Germany's Next Top Model" winner,
Barbara, of the popular reality show of the same name, the magazine declared that red was the new blonde!
In actual fact, only two percent of the world's population (and the German population) have naturally red
hair - caused by a mutation in the gene mc1r. The resulting change in the protein it controls causes those
who have this gene mutation to carry pheomelanin instead of the dark melanin in their skin, hair and eyes.
This gives them much more sensitive, light coloured skin and, in many case, lots of freckles.
Scientists from the Max Planck Institute for Evolutionary Anthropology in collaboration with their
colleagues at the universities in Barcelona and Leipzig have now discovered that one percent of the
Neanderthals in Europe had red hair - and it was definitely not dyed. The researchers tracked down the
Neanderthals' hair colour by means of genetic analysis: first, they attempted to multiply a piece of the
mc1r gene from an extract of Neanderthal DNA. In doing so, they found a variant that has never been
observed in modern humans.
Thanks to a series of complex tests, the molecular biologists were able to rule out the chance that the
experimental samples containing the variant may have been contaminated with modern human DNA, or
were a random result caused by damaged DNA or PCR errors (PCR, or polymerase chain reaction, is a
method of multiplying DNA). Functional tests then showed that this variant is much less active than the
normal human variant. "Gene variants with similarly reduced activity are also known in modern man -
although they are a result of other mutations," says Michael Hofreiter. "In people, they lead to red-coloured
hair. We can therefore assume that part of the Neanderthal population may have had red or light coloured
hair and possibly even lighter coloured skin," according to the paleoanthropologist.
Whether red hair in Neanderthals was considered particularly erotic or more of a turnoff is, of course,
something the scientists cannot say.
Original
.
.
The Neanderthal ‘‘chignon’’: Variation, integration, and homology
Philipp Gunz, Katerina Harvati*
.
.
Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany
Received 10 May 2006; accepted 31 August 2006
.
Received 10 May 2006; accepted 31 August 2006
.
.
Abstract
The occipital bun (‘‘chignon’’) is cited widely as a Neanderthal derived trait. It encompasses the posterior projection/convexity of the
occipital squama and is associated with lambdoid flattening on the parietal. A ‘hemibun’ in some Upper Paleolithic Europeans is thought by
some authors to indicate interbreeding between Neanderthals and early modern Europeans. However, ‘bunning’ is difficult to measure, and
the term has been applied to a range of morphological patterns. Furthermore, its usefulness in phylogenetic reconstruction and its homologous
status across modern and fossil humans have been disputed. We present a geometric morphometric study that quantitatively evaluates the
chignon, assesses its usefulness in separating Neanderthals from modern humans, and its degree of similarity to Upper Paleolithic ‘hemibuns.’
We measured the three-dimensional coordinates of closely spaced points along the midsagittal plane from bregma to inion and of anatomical
landmarks in a large series of recent human crania and several Middle and Late Pleistocene European and African fossils. These coordinate data
were processed using the techniques of geometric morphometrics and analyzed with relative warps, canonical variates, and singular warps. Our
results show no separation between Neanderthals and modern humans, including early modern Europeans, when the shape of the occipital plane
midsagittal-profile is considered alone. On the other hand, Neanderthals are well separated from both recent and fossil modern humans when
information about the occipital’s relative position and relative size are also included. Furthermore, the occurrence of a highly convex and posteriorly
projecting midline occipital profile (interpreted as the occipital bun) is highly correlated (>0.8) with a flat parietal midsagittal profile and
with antero-superiorly positioned temporal bones across both our recent and our fossil human samples. We conclude that the shape of the occipital
profile alone should not be considered an independent trait, as it is very tightly integrated with braincase shape. Our analysis does not
support differences in integration of the posterior midsagittal profile and the cranial base in Pleistocene and recent humans.
The occipital bun (‘‘chignon’’) is cited widely as a Neanderthal derived trait. It encompasses the posterior projection/convexity of the
occipital squama and is associated with lambdoid flattening on the parietal. A ‘hemibun’ in some Upper Paleolithic Europeans is thought by
some authors to indicate interbreeding between Neanderthals and early modern Europeans. However, ‘bunning’ is difficult to measure, and
the term has been applied to a range of morphological patterns. Furthermore, its usefulness in phylogenetic reconstruction and its homologous
status across modern and fossil humans have been disputed. We present a geometric morphometric study that quantitatively evaluates the
chignon, assesses its usefulness in separating Neanderthals from modern humans, and its degree of similarity to Upper Paleolithic ‘hemibuns.’
We measured the three-dimensional coordinates of closely spaced points along the midsagittal plane from bregma to inion and of anatomical
landmarks in a large series of recent human crania and several Middle and Late Pleistocene European and African fossils. These coordinate data
were processed using the techniques of geometric morphometrics and analyzed with relative warps, canonical variates, and singular warps. Our
results show no separation between Neanderthals and modern humans, including early modern Europeans, when the shape of the occipital plane
midsagittal-profile is considered alone. On the other hand, Neanderthals are well separated from both recent and fossil modern humans when
information about the occipital’s relative position and relative size are also included. Furthermore, the occurrence of a highly convex and posteriorly
projecting midline occipital profile (interpreted as the occipital bun) is highly correlated (>0.8) with a flat parietal midsagittal profile and
with antero-superiorly positioned temporal bones across both our recent and our fossil human samples. We conclude that the shape of the occipital
profile alone should not be considered an independent trait, as it is very tightly integrated with braincase shape. Our analysis does not
support differences in integration of the posterior midsagittal profile and the cranial base in Pleistocene and recent humans.
.
quinta-feira, 13 de dezembro de 2007
DNA NEANDERTAL (2006)
Sequencing and Analysis of
Neanderthal Genomic DNA
James P. Noonan,1,2 Graham Coop,3 Sridhar Kudaravalli,3 Doug Smith,1
Johannes Krause,4 Joe Alessi,1 Feng Chen,1 Darren Platt,1 Svante Pääbo,4
Jonathan K. Pritchard,3 Edward M. Rubin1,2*
.
Neanderthal Genomic DNA
James P. Noonan,1,2 Graham Coop,3 Sridhar Kudaravalli,3 Doug Smith,1
Johannes Krause,4 Joe Alessi,1 Feng Chen,1 Darren Platt,1 Svante Pääbo,4
Jonathan K. Pritchard,3 Edward M. Rubin1,2*
.
Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing andanalysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of
sequence identities between Neanderthal and chimpanzee at sites where the human genomic
sequence is different. These results enabled us to calculate the human-Neanderthal divergence
time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor ~706,000 years ago, and that the human and Neanderthal ancestral populations split ~370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.
1Mechanical and Aerospace Engineering, Cornell University,
.
sequence identities between Neanderthal and chimpanzee at sites where the human genomic
sequence is different. These results enabled us to calculate the human-Neanderthal divergence
time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor ~706,000 years ago, and that the human and Neanderthal ancestral populations split ~370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.
1Mechanical and Aerospace Engineering, Cornell University,
.
.
Ithaca, NY 14853, USA. 2Computing and Information
Science, Cornell University, Ithaca, NY 14853, USA.
*Present address: Department of Computer Science,
University of Vermont, Burlington, VT 05405, USA.
†To whom correspondence should be addressed. E-mail:
josh.bongard@uvm.edu
Science, Cornell University, Ithaca, NY 14853, USA.
*Present address: Department of Computer Science,
University of Vermont, Burlington, VT 05405, USA.
†To whom correspondence should be addressed. E-mail:
josh.bongard@uvm.edu
.
.
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