Not long ago, scientists used the DNA of one of the oldest English skeletons (10,000 years old) to find out what the first inhabitants of Britain looked like. However, the DNA of the ancient skeleton is taken not for the first time and reveals the amazing facts about our ancient ancestors. The rapid development of genome sequencing over the past few decades has opened a new window to the past.
Our ancestors slept with Neanderthals
Archaeologists have long guessed that modern people and Neanderthals lived together in Europe and Asia, but only recently did they become aware of their cohabitation.
In fact, after the first mitochondrial Neanderthal genome was sequenced in 2008 (the DNA located in the mitochondria of the cell), geneticists and archaeologists for a long time could not understand whether people are related to our closest relatives someone in some way or not.
When in 2010 was sequenced the complete genome of the Neanderthal, a comparison with the DNA of modern humans have shown that all non-African people have pieces of DNA of Neanderthals, implicated in the genome. This could happen if people and Neanderthals mixed up just 50,000 years ago. A few years later this was confirmed.
Confusion allowed Tibetans to live in the mountains
Ironically, our ancestors communicated with Neanderthals not just as friends. When DNA was sequenced from a petrified finger found in a cave in the Altai mountains in Siberia, and the finger was thought to belong to a Neanderthal man, a genetic analysis showed that it was actually a new species of man, different from, but closely related to the Neanderthals. The analysis of the full genome showed that these "Denis people" also had sex with our ancestors.
Tibetans, who live among the highest mountains in the world, are able to survive on altitudes where most people simply gasp in the absence of oxygen. Genetic analysis has shown that Tibetans, along with Ethiopian and Andean mountaineers, have special genetic adaptations that allow them to treat oxygen in rarefied mountain air.
Now we know that these genetic adaptations to altitude in Tibetans – they have a specific variant of the EPAS1 gene – have in fact been inherited through generic mating with the Denis people.
It turned out that improving immunity , metabolism and diet among modern people is also associated with useful genetic variants inherited as a result of this crossing with both Neanderthals and Denis people.
Our ancestors evolved surprisingly quickly
Crossing with other species explains Only a small part of human adaptations. DNA analysis shows us that as our ancestors wandered around the world, they evolved in different environments and adapted to food faster than previously thought.
For example, an obvious example of human adaptation is the development of lactose tolerance. The ability to digest milk after three years is not universal – and it was previously assumed that it spread in Europe along with Middle Eastern agriculture about 10,000 years ago.
But when we study human DNA over the past 10,000 years, this adaptation, which is now is a common occurrence in Northern Europe, was absent 4000 years ago, and even then it was quite a rare phenomenon. This means that the spread of lactose tolerance in Europe should have been incredibly rapid.
The first English were dark-skinned
The DNA of one of the first people in Britain, Cheddar Man, shows that he was most likely a dark-skinned and blue-eyed. And he also could not digest the milk.
Although it is curious and even somewhat surprising to learn that some of the first people who inhabit the island, now known as Britain, had dark skin and blue eyes, this striking combination is not at all so unpredictable, given that we learned about Paleolithic Europe from the DNA of the ancients. Dark skin was quite common among hunter-gatherers like Cheddar Man, who lived in Europe for thousands of years after he lived – and their blue eyes were from the Ice Age.
Immigrants from the East brought white skin to Europe
] So, if 10,000 years ago in Europe dark skin was common, how did the Europeans acquire their white skin? In Europe there are no hunter-gatherers anymore, and there are very few of them around the world. Agriculture replaced hunting as a way of life, and as is known, in Europe, agriculture has spread from the Middle East. Genetics revealed to us that this change is also associated with a significant movement of people.
We also know now that about 5000 years ago there was a large influx of people from Europe to Russia from the Russian and Ukrainian steppes (territorially). Together with DNA, these people brought domesticated horses and a wheel to Europe, and at the same time, probably a proto-Indo-European language, from which almost all modern European languages originated.
Most likely, white skin appeared in Europe along with them. It is believed that light skin pigmentation helps people better absorb sunlight and synthesize vitamin D.