Reading Neanderthals may not be able to turn nutrients into energy as efficiently as their competitors, the anatomically modern humans: their mitochondria, the tiny power plants within the body's cells, seem to have been geared towards the production of heat rather than the formation of high-energy compounds. This concludes a US-British research team from the building block sequence of the genome of these cell components, which was first published in August this year. Your heating mitochondria probably benefited the Neanderthals in the cold climate of the Ice Age? However, as the weather became warmer and more changeable, the poorer energy balance was more of a disadvantage and could have contributed to the extinction of the early humans. Mitochondria are the only components of the cell apart from the nucleus have their own genetic material. On it are the blueprints for a set of tools for the conversion of nutrients stored in energy. Some of this energy is released as heat, while the rest is converted into a molecule called ATP, a kind of universal energy currency for the cell. This was also the case with the Neanderthal man, who lived in Europe and western Asia until about 30, 000 years ago: the genetic material of his mitochondria is similar to that of humans today, an international research team had shown in August with the help of an analysis of a Neanderthal bone from Croatia,
In modern humans, the conversion of energy into ATP is generally very efficient and the heat fraction low. However, some previous studies have suggested that it is significantly elevated among residents of arctic areas? presumably an adaptation to the climatic conditions in order to be able to keep the body temperature in the constant cold better constant. Responsible for this are usually changes in the mitochondrial genome, which cause a kind of short circuit in the energy conversion chain.
Since the Neanderthals also had to cope with an extremely cold climate for a long time, there could have been a similar adaptation, suspected Patrick Chinnery of the University of Newcastle and his colleagues. They therefore re-examined some of the data from the Neanderthal heritage and actually found a bias that could have led to a similar short-circuit as found among Arctic dwellers.
Caution should be exercised when interpreting the results, Chinnery points out to the New Scientist: The published sequence is from a single Neanderthal man and may have been accidental or personal. Before the same change is not detected in a whole series of other individuals, mitochondrial involvement in the extinction of Neanderthals is merely a preliminary hypothesis. display
Patrick Chinnery (University of Newcastle) et al .: New Scientist, 27.11.2008 ddp / science.de? Ilka Lehnen-Beyel