Neanderthals died 40,000 years ago, but thanks to their DNA they are still all around us

Neanderthals died 40,000 years ago, but thanks to their DNA they are still all around us

The conversation

Neanderthals have been a reflection of our own humanity since their discovery in 1856. What we think we know about them has been molded and shaped to fit our cultural tendencies, social norms, and scientific norms. They went from diseased specimens to primitive subhuman forest cousins ​​to advanced humans.

We now know Homo neanderthalensis were very similar to ourselves and we even met them and crossed paths frequently. But why did they disappear, when we survived, thrived and eventually conquered the planet?

Neanderthals evolved over 400,000 years ago, most likely from an earlier ancestor A man from Heidelberg. They were very successful and spread in an area from the Mediterranean to Siberia. They were very intelligent, with brains on average larger than A wise man‘s.

They hunted big game, gathered plants, mushrooms and seafood, controlled fire for cooking, made composite tools, made clothing from animal skins, made beads from shells and could engrave symbols on the walls of caves. They cared for their young, old, and weak, made shelters for protection, lived through harsh winters and hot summers, and buried their dead.

Neanderthals encountered our ancestors many times over tens of thousands of years, and the two species shared the continent of Europe for at least 14,000 years. They even mated.

Human Evolution Chart
Our common ancestor lived less than a million years ago. Kjaergaard, Nielsen & Maslin, Author provided

Death of a species

The most significant difference between Neanderthals and us is that they died out around 40,000 years ago. The precise cause of their disappearance still eludes us, but we believe it is likely the result of a combination of factors.

First, the climate of the last ice age was highly variable, going from cold to hot and vice versa, which put pressure on animal and plant food sources and forced Neanderthals to constantly adapt to environmental changes. . Second, there have never been so many Neanderthals, with the overall population never exceeding tens of thousands.

They lived in groups of 5 to 15 individuals, against A wise man which had groups of up to 150 people. These small, isolated Neanderthal populations may have been increasingly genetically unsustainable.

Third, there was competition with other predators, especially the groups of modern humans that emerged from Africa around 60,000 years ago. We speculate that many Neanderthals may have been assimilated into the wider bands of A wise man.

Where is the evidence ?

Neanderthals have left many traces for us to examine tens of thousands of years later, most of which can be seen in the special exhibition we helped organize at the Natural History Museum of Denmark. Over the past 150 years, we’ve collected fossil bones, stone and wooden tools, found trinkets and jewelry they left behind, uncovered burials, and now mapped their genome from ancient DNA. . It appears that 99.7% of human DNA from Neanderthals and modern humans are identical and they are our closest extinct relatives.

Perhaps most surprising was the evidence of interbreeding that left traces of DNA in humans alive today. Many Europeans and Asians have between 1% and 4% Neanderthal DNA while Africans south of the Sahara have almost zero. Ironically, with a current world population of around 8 billion, this means there has never been more Neanderthal DNA on Earth.

Neanderthal man painting
99.7% human. Artist: Tom Björklund / Moesgård Museum, Author provided

The Neanderthal genome also helps us better understand what they looked like, as there is evidence that some Neanderthals developed pale skin and red hair long before A wise man. The many genes shared between Neanderthals and modern humans are linked to everything from the ability to taste bitter foods to the ability to speak.

We have also increased our knowledge of human health. For example, some Neanderthal DNA that might have benefited humans tens of thousands of years ago now appears to cause problems when combined with a modern Western lifestyle.

There are links to alcoholism, obesity, allergies, blood clotting and depression. Recently, scientists have suggested that an ancient genetic variant of Neanderthals may increase the risk of serious complications from contracting COVID-19.

hold a mirror

Like the dinosaurs, Neanderthals did not know what awaited them. The difference is that the dinosaurs suddenly disappeared following a giant meteor hit from space. The extinction of Neanderthals occurred gradually. They ended up losing their world, a comfortable home they had successfully occupied for hundreds of thousands of years that slowly turned against them, until existence itself became unsustainable.

In this sense, Neanderthals now serve a different purpose. We see our reflection there. They didn’t know what was happening to them and they had no choice but to continue down the path that eventually led to extinction. For our part, we are painfully aware of our situation and the impact we have on this planet.

Human activity is changing the climate and leading directly to a sixth mass extinction. We can reflect on the mess we got into and we can fix it.

If we don’t want to end up like the Neanderthals, we better pull ourselves together and work collectively for a more sustainable future. The Neanderthal extinction reminds us that we should never take our existence for granted.The conversation

Peter C. Kjaergaard, professor of evolutionary history and director of the Natural History Museum of Denmark, University of Copenhagen; Mark Maslin, Professor of Earth System Sciences, UCL, and Trine Kellberg Nielsen, Associate Professor, Department of Archeology and Heritage Studies, University of Aarhus

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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