researchers identify possible new human group with dna from bone - nytimes.c

8/9/2019 Researchers Identify Possible New Human Group With DNA From Bone - NYTimes.c

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earchers Identify Possible New Human Group With DNA From Bone - NYTimes.com

//www.nytimes.com/2010/03/25/science/25human.html?hpw=&pagewanted=print[3/24/2010 8:24:08 PM]

according to radiocarbon dating. At that time, toward the end of the Pleistocene Ice Age, which ended

0,000 years ago, the climate was probably much colder. The people of the new lineage presumably wor

lothes, Dr. Krause said, because chimpanzees and gorillas cannot withstand much cold, suggesting that

alone is inadequate protection.

The artifacts found in the cave in the same layer as the finger bone include ornaments and a bracelet tha

are typical of modern human sites from the Upper Paleolithic age in Europe. These are puzzling artifact

be found with a nonmodern human species. But bones can move up and down in archaeological sites, at is hard to know if the finger bone is truly associated with these artifacts, Dr. Krause said, even though

here is little sign of mixing in the caves layers.

The valley beneath the Denisova cave 30,000 years ago would have been mostly a steppe, or treeless

grassland, according to pollen analysis, and it was roamed by ice-age species like the woolly mammoth a

woolly rhino, Dr. Krause said.

The region was inhabited by both Neanderthals and modern humans at that time. Counting the new hum

ineage, three human species may have lived together in proximity. So the picture of the humans arounn the late Pleistocene gets a lot more complex and a lot more interesting, Dr. Paabo said.

The standard view has long been that there were three human migrations out of Africa those of Homo

rectus; of the ancestor of Neanderthals; and finally, some 50,000 years ago, of modern humans. But in

2004, archaeologists reported that they had found the bones of miniature humans who lived on the

ndonesian island of Flores until 13,000 years ago, posing a serious problem for this view. The new linea

s the second such challenge, and it suggests that human migrations out of Africa, though far from

ontinuous, were more frequent than supposed.

We are learning more and more what a luxuriant evolutionary tree humans have had, said Ian Tatters

a paleoanthropologist at theAmerican Museum of Natural Historyin New York. The tree during

volutionary time has kept sprouting new branches, all but one of which die off, before the process is

epeated.

As recently as 30,000 years ago, it now appears, there were five human species in the world: Homo erec

he little Floresians, Neanderthals, modern humans and the new lineage from the Denisova cave. This is

imilar to the situation two million years ago, when four hominid species are known to have lived in the

Turkana Basin of Kenya, Dr. Tattersall said.

We think its normal to be alone in the world as we are today, Dr. Tattersall said, and to see human

volution as a long trend leading to Homo sapiens. In fact, the tree has kept generating new branches th

get cut off, presumably by the sole survivor. The fossil record is very eloquent about this, and its telling

we are an insuperable competitor, Dr. Tattersall said. Modern humans edge over other species probabl

merged from their ability to process information: We can invent alternatives in our heads instead of

accepting nature as it is, Dr. Tattersall said.
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earchers Identify Possible New Human Group With DNA From Bone - NYTimes.com

//www.nytimes.com/2010/03/25/science/25human.html?hpw=&pagewanted=print[3/24/2010 8:24:08 PM]

f the nuclear DNA of the Denisova child should differ as much as its mitochondrial DNA does from that

Neanderthals and modern humans, the case for declaring it a new species would be strengthened. But it

would be unusual, if not unprecedented, for a new species to be recognized on the basis of DNA alone.

n new excavations starting this summer, archaeologists will look for remains more diagnostic than the

inger bone. Researchers will also begin re-examining the fossil collections in museums to see if any

wrongly assigned bones might belong instead to the new lineage, Dr. Krause said.

researchers identify possible new human group with dna from bone - nytimes.c

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