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Genetic traces of unknown humanoid in DNA of African people
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September 3rd, 2012 - Genetic research among 15 hunter-gatherers from Africa has yielded three surprise findings. For example, indications have been found for the existence of an unknown humanoid. This species must have lived between 20,000 and 80,000 years ago alongside the ancestors of modern humans in Africa. Genes were also found that are partly responsible for the small stature of Pygmies and genetic indications were seen for the adaptation of hunter-gatherers to local conditions.
The researchers mapped the genome of three isolated living groups in Africa, which still live as hunter-gatherers. They mapped a total of 13.4 million genetic variants of which 5 million have never previously been found in other populations.
Earlier research had revealed that people in Europe and Asia possess DNA from other humanoids; now this appears to be the case for African populations as well. The researchers have attributed part of the unknown DNA to a new, previously unknown species. This must have lived alongside the ancestors of modern humans who evolved about 200,000 years ago in Africa. According to the genetic traces there must have been sexual contact between the two species as well. Researchers have calculated that this must have happened between 20,000 and 80,000 years ago. It probably concerns a 'cousin' of the Neanderthal. The DNA of the Neanderthal, however, is slightly different. Genetic traces have now been found for the existence of this new species but the associated fossil evidence has yet to be found.
In Pygmies, the researchers found a variant of the gene responsible for the development of the pituitary gland, a small part of the brain related to hormones and growth. This could be the cause of their short stature and the early age at which they have children.
Finally the researchers saw genetic indications for the adaptation of the hunter-gatherers to local conditions. Although the three groups live in the same manner, they were found to be genetically very different from each other. The researchers found the differences in genetic adaptations in the areas of the immune system, smell and taste. These variations ensure that the groups are adapted to the local conditions, such as prevalent diseases and the food supply, which can differ per area.
The 15 hunter-gatherers investigated were five Pygmies from Cameroon, and five Hadza and five Sandawe from Tanzania who speak a click language. A growing volume of human DNA is being read out (sequenced) because, for example, the price of sequencing continues to fall. Africans are still underrepresented when it comes to sequencing the human genome even though humans originated from Africa and many African populations are genetically very different from each other.
Dutch researchers published about this work together with their American colleagues in the cover story of the renowned journal Cell. Dr Clara Elbers and Dr Bart Ferwerda both received a NWO Rubicon grant to acquire foreign work experience. They are working at the University of Pennsylvania (US) on research led by professor Sarah Tishkoff.
[link to io9.com]
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