Nova visão sobre o DNA arcaico reescreve a história da evolução humana

terça-feira, agosto 08, 2017

Early history of Neanderthals and Denisovans

Alan R. Rogers a,1, Ryan J. Bohlender b, and Chad D. Huff b 

Author Affiliations

aDepartment of Anthropology, University of Utah, Salt Lake City, UT 84112;

bDepartment of Epidemiology, MD Anderson Cancer Center, Houston, TX 77030

Edited by Richard G. Klein, Stanford University, Stanford, CA, and approved July 7, 2017 (received for review April 18, 2017)

These population trees with embedded gene trees show how mutations can generate nucleotide site patterns. The four branch tips of each gene tree represent genetic samples from four populations: modern Africans, modern Eurasians, Neanderthals, and Denisovans. In the left tree, the mutation (shown in blue) is shared by the Eurasian, Neanderthal and Denisovan genomes. In the right tree, the mutation (shown in red) is shared by the Eurasian and Neanderthal genomes. Credit: Alan Rogers, University of Utah

Significance

Neanderthals and Denisovans were human populations that separated from the modern lineage early in the Middle Pleistocene. Many modern humans carry DNA derived from these archaic populations by interbreeding during the Late Pleistocene. We develop a statistical method to study the early history of these archaic populations. We show that the archaic lineage was very small during the 10,000 y that followed its separation from the modern lineage. It then split into two regional populations, the Neanderthals and the Denisovans. The Neanderthal population grew large and separated into largely isolated local groups.

Abstract

Extensive DNA sequence data have made it possible to reconstruct human evolutionary history in unprecedented detail. We introduce a method to study the past several hundred thousand years. Our results show that (i) the Neanderthal–Denisovan lineage declined to a small size just after separating from the modern lineage, (ii) Neanderthals and Denisovans separated soon thereafter, and (iii) the subsequent Neanderthal population was large and deeply subdivided. They also (iv) support previous estimates of gene flow from Neanderthals into modern Eurasians. These results suggest an archaic human diaspora early in the Middle Pleistocene.

human evolution archaic admixture introgression Neanderthals Denisovans

Footnotes

1To whom correspondence should be addressed. Email: rogers@anthro.utah.edu.

Author contributions: A.R.R. and C.D.H. designed research; A.R.R. and R.J.B. performed research; A.R.R. and R.J.B. analyzed data; and A.R.R. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1706426114/-/DCSupplemental.

Freely available online through the PNAS open access option.

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