Scientists find evidence of another possible human species

The fossilized bone fragment from the pinkie finger of a child has intrigued German researchers as they believe it belongs to some human-like creature different from our species, Homo sapiens.

Exhaustive test were conducted on DNA extracted from the fifth digit of the hominin that was found in 2008 in a Denisova Cave in the Altai Mountains, and the report was published online in the journal Nature.

Earth was more crowded than thought
The team, led by anthropologists Johannes Krause and Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, believes that it belongs to a previously unknown type of humans between the Homo sapiens and the Neanderthals.

The findings suggest that “40,000 years ago, the planet was more crowded than we thought,” wrote evolutionary biologist Terence A. Brown of the University of Manchester.

The Denisova Cave shows signs of having been used by humans and their relatives periodically for at least 125,000 years.

The DNA sequences suggest that the new found species had the same ancestor as both modern humans and Neanderthals about 1 million years ago. This species is, however, farther from the modern human than the Neanderthal.

The pinkie bone found by German scientists is of a child between seven to nine years of age but the gender of the child could not be determined.

New species and homo sapiens had common ancestors
The DNA sequences suggest that the new found species had the same ancestor as both modern humans and Neanderthals about one million years ago. This species is, however, farther from the modern human than the Neanderthal.

The evolutionary tree of humans will see some gaps filled after this study, which shows that the Denisova hominin lineage came out and separated before modern human could separate from Neanderthal.

The authors have suggested that the Denisova individual inhabited the Earth between 30,000 and 50,000 years ago. Interestingly, Neanderthals are believed to be present at about the same time, only living some 100 km away.

Further probing required
The DNA sequences analyzed this time were from tiny organelles within the cells called the mitochondria. Some evidence on lineage could be established from these DNA sequences but it hardly gives any idea on the characteristics of the individual.

Scientists are now trying to sequence the DNA from the nucleus of the cells, which is more difficult to obtain but will give a better picture of the Denisova individual.

Though evidence indicates this to be a new species, “we are not saying this is a new species,” said Paabo at a news conference. Confirmation will be made only after the whole sequence is completely analyzed.