DNA points to new hominid species that lived 40,000 years ago

Pinkie DNA points to hominid species that lived 40,000 years ago
Thursday, March 25, 2010
Thomas H. Maugh II, Los Angeles Times

LOS ANGELES " DNA from a 40,000-year-old pinkie finger, belonging to a child and found in a cave in Siberia, indicates that the bone is from a previously unknown family of human relatives that lived among Neanderthals and modern humans, German researchers said Wednesday.

The discovery, if confirmed by research already under way, would mark the first time that a previously unknown species of hominid has been identified solely on the basis of DNA sequencing, the team reported online in the journal Nature. It also suggests that other currently unknown species could be similarly identified.

With the recent discovery of the Hobbit-like species Homo floriensis, which survived in Indonesia until 13,000 years ago, the evidence now indicates that at least four species of human-like creatures walked the Earth at the same time.

The find suggests that "40,000 years ago, the planet was more crowded than we thought," evolutionary biologist Terence A. Brown of the University of Manchester wrote in an editorial accompanying the report.

The pinkie bone, from a child age 7 to 9 but of unknown gender, was found in the Denisova Cave in southern Siberia. The cave shows signs of being occupied by humans and their relatives periodically for at least 125,000 years.

The new species shared an ancestor with both modern humans and Neanderthals about 1 million years ago, based on the DNA sequences, according to the team led by anthropologists Johannes Krause and Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

The DNA sequences are from mitochondria, the tiny organelles within cells that provide power for all the activities of life. They provide a useful indicator of lineage but say little about the physical characteristics of the whole organism.

But Krause and his colleagues are working to sequence the more-difficult-to-analyze DNA in the nucleus of cells in the hopes that that information will provide a better picture of the form of life they appear to have discovered.

Until the team has a complete sequence of nuclear DNA, "we are not saying this is a new species," Paabo said at a news conference, but all the evidence so far suggests it is.