Forscher des Max-Planck-Instituts für evolutionäre Anthropologie in Leipzig haben eine gänzlich neue Menschenform entdeckt. Sie hatten Erbmaterial aus einem in Sibirien entdeckten Fingerknochen mit dem von Neandertalern und heute lebenden Menschen verglichen.
Der Fund weise auf eine weitere Auswanderungswelle aus Afrika hin, die sich von den Wanderungen des Homo erectus sowie der Vorfahren der Neandertaler und modernen Menschen unterscheide.Analysiert die mitochondriale DNA aus den «Kraftwerken» der Zelle, die ausschließlich mütterlicherseits vererbt wird. Der Finger gehörte demnach einer Menschenform, die vor mehr als 30 000 Jahren in dem Gebirge in Zentralasien lebte. Das Alter des Fossils deute darauf hin, dass die Gruppe parallel zu Neandertalern und modernen Menschen gelebt haben könnte.[Links nur für registrierte Nutzer]Der gemeinsame Vorfahr der drei Menschenformen habe der Analyse nach vor etwa einer Million Jahren gelebt, schreiben die Forscher in «Nature». Homo erectus verließ nach heutigem Stand der Forschung vor etwa 1,9 Millionen Jahren Afrika, die Vorfahren der Neandertaler begaben sich vor rund 500 000 bis 300 000 Jahren auf Wanderschaft, die des modernen Menschen vor etwa 50 000 Jahren.
If further work does support the initial conclusions, the discovery would mark the first time that an extinct human relative had been identified by DNA analysis. It would also suggest that ice-age humans were more diverse than had been thought. Since the late nineteenth century, researchers have known that two species of Homo — Neanderthals and modern humans — coexisted during the later part of the last ice age. In 2003, a third species, Homo floresiensis, was discovered on the island of Flores in Indonesia, but there has been no sign of this tiny 'hobbit' elsewhere. The relative identified in Siberia, however, raises the possibility that several Homo species ranged across Europe and Asia, overlapping with the direct ancestors of modern people.The differences imply that the Siberian ancestor branched off from the human family tree a million years ago, well before the split between modern humans and Neanderthals. If so, the proposed species must have left Africa in a previously unknown migration, between that of Homo erectus 1.9 million years ago and that of the Neanderthal ancestor Homo heidelbergensis, 300,000 to 500,000 years ago.Researchers not involved in the work applauded the findings but cautioned against drawing too many conclusions from a single study. "With the data in hand, you cannot claim the discovery of a new species," says Eske Willerslev.
Willerslev emphasizes that, on its own, the mtDNA evidence does not verify that the Siberian find represents a new species because mtDNA is inherited only from the mother. It is possible that some modern humans or Neanderthals living in Siberia 40,000 years ago had unusual mtDNA, which may have come from earlier interbreeding among H. erectus, Neanderthals, archaic modern humans or another, unknown species of Homo. Only probes of the nuclear DNA will properly define the position of the Siberian relative in the human family tree.[Links nur für registrierte Nutzer]"It is fascinating that molecular studies make a contribution in palaeontology where there is little or no morphology preserved," he says. "It is clear we stand just in the beginning of many fascinating developments."
[Links nur für registrierte Nutzer]