The ancestors with no descendants

Venus of Mal’ta, a figurine from a site in eastern Siberia (source). She comes from a population that was related to modern Europeans and Amerindians but not to modern native Siberians. The Mal’ta Siberians died out at the height of the last ice age and were replaced by people spreading north from East Asia and west from Beringia.

On the eve of the last ice age, Siberia was home to a people who were related to modern Europeans and Amerindians but not to modern native Siberians. So concludes an analysis of DNA from the remains of a boy who lived 24,000 years ago at Mal’ta near Lake Baikal, Siberia.

They found that a portion of the boy's genome is shared only by today's Native Americans and no other groups, showing a close relationship. Yet the child's Y chromosome belongs to a genetic group called Y haplogroup R, and its mitochondrial DNA to a haplogroup U. Today, those haplogroups are found almost exclusively in people living in Europe and regions of Asia west of the Altai Mountains, which are near the borders of Russia, China, and Mongolia.

One expected relationship was missing from the picture: The boy's genome showed no connection to modern East Asians. DNA studies of living people strongly suggest that East Asians—perhaps Siberians, Chinese, or Japanese—make up the major part of Native American ancestors (Balter, 2013).

These findings are consistent with earlier ones. Strong dental and cranial affinities exist between remains from the same site and those of Upper Paleolithic Europeans (Alexeyev and Gokhman, 1994). Also, when we compare the Clovis sites of early Amerindians (13,000 BP) with early European and Siberian sites (20,000-15,000 BP), we find many features in common: characteristic lithic technology, grave goods with red ocher, and sites with small shallow basins (Goebel, 1999; Haynes, 1980; Haynes, 1982).

What do these findings tell us? I would propose the following:

1. When the last ice age began some 25,000 years ago, a single population of nomadic hunters occupied the steppe-tundra that stretched from southwestern France to Beringia.

2. Ancestral East Asians had already split away from this proto-Eurasian population. They had probably adapted to life farther south in the more temperate environments of what is now north China. The Ainu may be an evolutionarily conservative branch of these East Asians.

3. At the height of the last ice age some 20,000 to 17,000 years ago, Siberia became virtually devoid of human life (Graf, 2009a; Graf, 2009b). Proto-Eurasians survived in refugia in parts of Europe to the west and in coastal regions of northeast Asia, Beringia and northwest North America to the east. Kennewick Man (c. 9,000-10,000 BP) may have been an example of this refuge population.

4. Siberia was then repeopled by two streams of settlement. One was composed of ‘Kennewickians’ spreading westward and inland from coastal refugia. The other stream was composed of early East Asians spreading northward.

5. This new mixed population of eastern Siberia and Beringia would later spread eastward into the interior of post-glacial North America around 13,000 years ago. These people were the early Amerindians of the Clovis culture.

It would be interesting to know what the reconstructed Mal’ta genome tells us about the skin, hair, and eye color of the proto-Eurasians. Were they pale-skinned with a diverse palette of hair and eye colors, like modern Europeans? Or were they brown-skinned with black hair and brown eyes, like modern Amerindians?  Probably the second possibility, given that the European color scheme seems to be a later evolutionary development—11,000 to 19,000 years ago for white skin and probably the same time frame for diversification of hair and eye color (Beleza et al., 2013). The Mal’ta people might have gone on to develop the same characteristics during this time frame, but they all died out at the height of the last ice age. 

In short, the Mal’ta people probably looked very much like native Indians with a more European skull shape, perhaps like the Ainu of northern Japan or the Kennewick humans of North America. 

References

Alexeyev, V.P., and I.I. Gokhman. (1994). Skeletal remains of infants from a burial on the Mal'ta Upper Paleolithic site, Homo, 45, 119‑126. 

Balter, M. (2013). Ancient DNA links Native Americans with Europe, Science, 342, 409-410.

http://www.sciencemag.org/content/342/6157/409.full

Beleza, S., A. Múrias dos Santos, B. McEvoy, I. Alves, C. Martinho, E. Cameron, M.D. Shriver, E.J. Parra, and J. Rocha. (2013). The timing of pigmentation lightening in Europeans, Molecular Biology and Evolution, 30, 24-35.

http://www.utm.utoronto.ca/~parraest/profile/PDF%20files/Beleza-2012(Mol.Biol.Evol.).pdf 

Goebel, T. (1999). Pleistocene human colonization of Siberia and peopling of the Americas: An ecological approach, Evolutionary Anthropology, 8, 208‑227.

http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1520-6505(1999)8:6%3C208::AID-EVAN2%3E3.0.CO;2-M/abstract

Graf, K.E. (2009a). “The Good, the Bad, and the Ugly”: evaluating the radiocarbon chronology of the middle and late Upper Paleolithic in the Enisei River valley, south-central Siberia. Journal of Archaeological Science, 36, 694–707.

http://www.centerfirstamericans.com/cfsa-publications/Graf-JAS2009-36-694.pdf

Graf, K.E. (2009b). Modern human colonization of the Siberian Mammoth Steppe: A view from South-Central Siberia. In M. Camps, P. Chauhan (eds.), Sourcebook of Paleolithic transitions (pp. 484-496), Springer Science & Business Media.

Haynes, C.V. (1982). Were Clovis progenitors in Beringia? In D.M. Hopkins (ed). Paleoecology of Beringia, (pp. 383‑398), New York: Academic Press. 

Haynes, C.V. (1980). The Clovis culture, Canadian Journal of Anthropology, 1, 115‑121.