3 research outputs found
Multiple Deeply Divergent Denisovan Ancestries in Papuans
Genome sequences are known for two archaic
hominins—Neanderthals and Denisovans—which
interbred with anatomically modern humans as
they dispersed out of Africa. We identified high-confidence
archaic haplotypes in 161 new genomes
spanning 14 island groups in Island Southeast
Asia and New Guinea and found large stretches of
DNA that are inconsistent with a single introgressing
Denisovan origin. Instead, modern Papuans carry
hundreds of gene variants from two deeply divergent
Denisovan lineages that separated over 350
thousand years ago. Spatial and temporal structure
among these lineages suggest that introgression
from one of these Denisovan groups predominantly
took place east of the Wallace line and continued
until near the end of the Pleistocene. A third Denisovan
lineage occurs in modern East Asians. This
regional mosaic suggests considerable complexity
in archaic contact, with modern humans interbreeding
with multiple Denisovan groups that were
geographically isolated from each other over deep
evolutionary time
Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave
Denisova Cave in the Siberian Altai (Russia) is a key site for understanding the complex relationships between hominin groups that inhabited Eurasia in the Middle and Late Pleistocene epoch. DNA sequenced from human remains found at this site has revealed the presence of a hitherto unknown hominin group, the Denisovans1,2, and high-coverage genomes from both Neanderthal and Denisovan fossils provide evidence for admixture between these two populations3. Determining the age of these fossils is important if we are to understand the nature of hominin interaction, and aspects of their cultural and subsistence adaptations. Here we present 50 radiocarbon determinations from the late Middle and Upper Palaeolithic layers of the site. We also report three direct dates for hominin fragments and obtain a mitochondrial DNA sequence for one of them. We apply a Bayesian age modelling approach that combines chronometric (radiocarbon, uranium series and optical ages), stratigraphic and genetic data to calculate probabilistically the age of the human fossils at the site. Our modelled estimate for the age of the oldest Denisovan fossil suggests that this group was present at the site as early as 195,000 years ago (at 95.4% probability). All Neanderthal fossils—as well as Denisova 11, the daughter of a Neanderthal and a Denisovan4—date to between 80,000 and 140,000 years ago. The youngest Denisovan dates to 52,000–76,000 years ago. Direct radiocarbon dating of Upper Palaeolithic tooth pendants and bone points yielded the earliest evidence for the production of these artefacts in northern Eurasia, between 43,000 and 49,000 calibrated years before present (taken as AD 1950). On the basis of current archaeological evidence, it may be assumed that these artefacts are associated with the Denisovan population. It is not currently possible to determine whether anatomically modern humans were involved in their production, as modern-human fossil and genetic evidence of such antiquity has not yet been identified in the Altai region