Ancient DNA Reveals Early Human-Neanderthal Interactions #

Oldest Homo Sapiens DNA in Europe Sheds Light on Shared History #

The oldest known Homo sapiens DNA in Europe has been recovered from human remains found in Germany. The ancient genomes, sequenced from 13 bone fragments unearthed in a cave beneath a medieval castle in Ranis, belonged to six individuals who lived in the region around 45,000 years ago.

These genomes carried evidence of Neanderthal ancestry, indicating that the ancestors of these early humans likely encountered and interbred with Neanderthals about 80 generations or 1,500 years earlier.

The interbreeding between early humans and Neanderthals is now believed to have occurred over an extended period, starting about 50,500 years ago and ending around 43,500 years ago. The peak of this activity was around 47,000 years ago.

This interspecies interaction left a genetic legacy still traceable in humans today, with Neanderthal DNA making up between 1% and 3% of modern human genomes.

The research revealed that certain genetic variants inherited from Neanderthals were beneficial to humans as they lived through the last ice age, conferring advantages related to immune function, skin pigmentation, and metabolism.

However, some regions of the human genome, termed “archaic deserts,” are devoid of Neanderthal genes. These areas likely developed quickly after interbreeding, possibly due to resulting birth defects or diseases that affected offspring survival.

The individuals living at Ranis had 2.9% Neanderthal ancestry, similar to most people today. They had dark skin, dark hair, and brown eyes, possibly reflecting their relatively recent arrival from Africa.

These early Europeans were part of a pioneer population that eventually died out, leaving no trace of ancestry in people alive today. This extinction, along with that of other ancient human lineages around 40,000 years ago, suggests that Homo sapiens may not have played a direct role in the demise of Neanderthals.

The new timeline helps scientists better understand when humans left Africa and migrated around the world. It suggests that the main wave of migration out of Africa was essentially complete by 43,500 years ago.

Despite these revelations, many questions remain unanswered. It’s still unclear why people in East Asia today have more Neanderthal ancestry than Europeans, or why Neanderthal genomes from this period show little evidence of Homo sapiens DNA.

“We were far more similar than we were different. The differences that we imagined between these groups to be very big, actually, were very small, genetically speaking. They seem to have mixed with each other for a long period of time and were living side by side for a long period of time.”

This research provides a powerful perspective on human migration and Neanderthal introgression, offering new insights into this crucial period of human evolution.