The findings also suggest that genetic diversity may have been higher in earlier Neandertal periods relative to later periods that approached the arrival of humans in Europe. Changes in genetic diversity over time are thought to reflect population events, such as low-population bottlenecks caused by disease or environmental change, as well as the influence of random genetic change. The findings are reported in the June 6th issue of Current Biology by a group of researchers including Ludovic Orlando and led by Catherine Hänni of Ecole Normale Supérieur in Lyon, France.
Neandertals were the only representatives of the genus Homo in Europe during most of the last 300,000 years, becoming extinct shortly after the arrival of modern humans on the continent around 30,000 years ago. Traces of mitochondrial DNA (mtDNA) sequences still present in fossilized bones have been used in past studies in an effort to identify and track the potential genetic legacy of Neandertals among modern Europeans. Though such genetic continuity would have been the hallmark of interbreeding between modern humans and Neandertals at the time of their European coexistence, the mtDNA sequences from the nine neandertal specimens that have been analyzed to date – and that lived around the time of the cohabitation period – do not match those found among modern humans, suggesting that little, if any, interbreeding took place.
In their new work, Dr. Hänni and colleagues now report the oldest Neandertal mtDNA sequence ever recovered. The Neandertal specimen analyzed consists in a molar of a 10-12 year-old child that lived in the Meuse valley (Scladina cave, Belgium) around 100,000 years ago. The specimen yielded 123bp of mtDNA – a very short section of DNA by modern sequencing standards, but a technical feat considering the very ancient source of tissue. The reason for choosing such an old specimen was simple: it unambiguously predates the period when Neandertals cohabited with modern humans. By comparing this sequence with already published – and considerably younger – Neandertal sequences, the researchers sought to reveal whether the Neandertal mtDNA pool exhibited long-term stability or drastic modification around the time of cohabitation with modern humans. There was a second reason to pay attention on the Scladina molar: it has only been discovered very recently. This means that all individuals who have been in contact with it are known, and their DNA could be sequenced to detect any possible contamination of the Neandertal sample by modern human DNA.
The Neandertal sequence from Scladina confirms that Neandertals and modern humans were only distant relatives – Neandertal sequences are all closer to each other than to any known human sequence. But the study also reveals that the genetic diversity of Neandertals has been underestimated. Indeed, the mtDNA from the Scladina sample is more divergent relative to modern humans than is mtDNA from recent Neandertals, suggesting that Neandertals were a more genetically diverse group than previously thought.
Heidi Hardman | EurekAlert!
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The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
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