7th May 2019
Neanderthals, Denisovians and Modern Humans
Pedro Horta
Denisovans, Modern Humans and Neanderthals: What we know so far
The last ten years of research in Paleolithic Archaeology have deeply changed what was previously known about our origins and ancestry. Humans as a species (Homo sapiens) were thought to have appeared sometime in the middle late Pleistocene in Africa. Taking into account fossil finds, this event took place around 200 000 years ago. This idea was reinforced by the Omo Kibish skull (~195 000 years ago) and other finds from Herto, Skhul and Qafzeh. However, the finds in Jebel Irhoud, Morocco have pushed that date by another 100 000 years, placing the emergence of modern humans as early as 300 000 years ago (Hublin et. al 2017).
Moreover, during this time Western Eurasia was occupied by Neanderthals for approximately 400 000 years. Neanderthals lived and thrived in this territory until the arrival of modern humans in Europe, roughly between 45-40 000 years ago. While they shared similarities with modern humans, Neanderthals were specific in the ecological niches they explored and their material culture. Often considered to be our closest relatives, genetic data shows that modern humans separated from them sometime between 400 and 700 000 years ago. Despite this, genetics show that modern day European populations share up to 4% of DNA with Neanderthals, indicating that there was some interbreeding between the two species in the last 50 000 years (Hajdinjak et. al, 2018).
It was previously thought that Neanderthals had expanded all the way up to the Far East, but recent evidence of a new species has emerged in Denisova cave in the Altai Mountains, Siberia. Amongst a large quantity of faunal remains, one finger bone was found that was neither animal, modern human nor Neanderthal. Paleogenetic studies revealed that this bone belonged to another hominin species later labeled as Denisovans (Krause et. al 2010). This species seems to have separated from humans together with Neanderthals roughly 700 000 years ago. Interestingly, Denisovans shared up to 17% DNA with Neanderthals (Slon et. al, 2018), which shows they were much closer relatives with each other than with modern humans. Furthermore, modern day populations in South East Asia share approximately 5% of DNA with Denisovans, which in itself is evidence that they interbred with modern humans at some point.
Genetics show that these species met and interbred, but does the archaeological evidence support this? Furthermore, how similar were these species from a biological, ecological and cultural point of view? This lecture aims explore these topics by taking into consideration the most current data available in the literature. This will be done in three different steps: first, by interpreting the data on each species’ biology and culture; secondly, by exploring their differences and similarities; and lastly their eventual contact leading up to the extinction of both Neanderthals and Denisovans and their incorporation into the modern human DNA sequence.
References
Hajdinjak, M. et al. Reconstructing the genetic history of late Neanderthals. Nature 555, 652–656 (2018).
Hublin, J. et al. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens. Nature 558, (2017).
Krause, J. et al. The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature 464, 894–897 (2010).
Slon, V. et al. The genome of the offspring of a Neanderthal mother and a Denisovan father. Nature 56, 113-116 (2018).
Pedro Horta is a Paleolithic archaeologist interested in the evolution of hominin adaptation and migration strategies from the earliest stone tool industries to the more complex stone tools used by modern humans. He is currently a PhD student and a Research fellow at ICArEHB, University of Algarve, where he completed his MA and BA. His ongoing PhD project is generating new data on how bipolar stone tool strategies impacted the arrival and settlement of early modern humans in Europe through a combination of controlled experiments, 3D scanning software and stone tool analysis. He has excavated a number of Paleolithic sites in Europe and North Africa and is currently involved with projects in Southern Portugal (Vale Boi and Gruta da Companheira) and Bulgaria (Bacho Kiro). Both projects are focused on hominin adaptations just prior and after the arrival of modern humans in Europe, a subject which Horta has mainly focused and published on.
