Ronald Cole-Turner: Transcending Evolution

Reconstruction of a Neanderthal, 2006, by Stefan Scheer, from Stefanie Krull, Neanderthal Museum Picture Library

Human-Neanderthal Interbreeding: When and Where?

Comparison between Neanderthal and anatomically modern human genomes shows a history of interbreeding. Some living human beings—those with ancestry in Europe and Asia—carry the results of that interbreeding in their DNA. Those with ancestry in sub-Saharan Africa typically do not.

We also know that Neanderthals lived in Eurasia from 230,000 until about 30,000 years ago. Where they came from or why they disappeared remains an open question. And we know that anatomically modern humans first appear in Africa at least 200,000 years ago. Some of them made their way to Asia and Europe sometime in the last 100,000 years.

So when did modern human-Neanderthal interbreeding last occur? Did it occur deep in our past, before modern humans and Neanderthal ancestors left Africa? Or did it occur after both left Africa, sometime—in other words—within the past 100,000 years?

A new study claims to find evidence that the interbreeding occurred out of Africa. Researchers argue that on the basis of careful analysis of the shared DNA, the most recent interbreeding occurred sometime between 37,000 and 86,000 years ago.

If so, it is pretty strong evidence that the interbreeding occurred after anatomically modern human left Africa. This may have occurred in the Middle East, researchers point out, but probably not just at the beginning of the modern human migration out of Africa. The most recent interbreeding, they conclude, occurs well after this 100,000 date, suggesting ”a more recent period, possibly when modern humans carrying Upper Paleolithic technologies expanded out of Africa.”

This would mean the conceptual challenge posed by the modern human-Neanderthal interbreedng remains clearly in front of us. What is the human species? Were Neanderthals human? And what are we to make of our new insight into modern human diversity. All puzzling questions, to be sure.

A version of this post first appeared on Enhancing Theology.

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Reader Comments

Anthropologists are using the word "human" to apply to any species within the genus Homo and have been doing so for several years. The link to the article does not work. The last one I looked at that looked at Neandertal alleles in H. sapiens was unsure whether the alleles were from our common ancestor or from interbreeding. I am still going to wait awhile before I accept any conclusions about inbreeding, since the morphological evidence from the fossils does not support it.

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