On a mild morning in August 1856, two Italian workers enlarged one of the entrances to the Neander Valley, adjacent to the River Dossel, in the German state of North Rhine-Westphalia. On limestone, this region has been a source of this type of rock for centuries.

When removing the sediments, the two workers discovered a large number of fossilized bones at a depth of 60 cm, which they thought were ordinary bones, so they threw them aside and continued their work.

But the owner of the place, and it was called "Wilhelm Beckershoff", assumed that they were the remains of a cave bear, so he gave them to a fossil collector he knows, who passed them to a newspaper, and a whole year passed from that point until we reached a surprise that was undoubtedly the biggest at the time of its issuance, as scientists confirmed that they had not They have never seen a specimen like that: it resembled humans, but with an oval-shaped skull with low foreheads and very distinct foreheads along with thick and strong body bones, this, it seemed, was not human at all.

After about ten years, this became the first fossil called from the fossils of hominins, and of course it took its name from the area of ​​its discovery. Yesterday, October 3, 2022, when Swedish scientist Svante Pääbo, a senior researcher from the Max Planck Institute for Evolutionary Anthropology, was awarded the Nobel Prize in Medicine and Physiology for "his discoveries relating to the genomes of extinct hominins and human evolution," according to Official Nobel Committee Statement.

Svant Papau, winner of the 2022 Nobel Prize in Medicine and Physiology. (Reuters)

A short history of the human race

Well, it is complicated, and full of confusing conventions, so let's start by getting to know the genus "Homo", which simply means - the human race. The word Homo basically means "human" in Latin.

According to evolutionary biology, only the species Homo sapiens is left of this genus, which is represented by everyone who reads this report. All modern humans are Homo sapiens.

As for the rest of the human species, which seem to be many, they became extinct for reasons that we are trying to identify until now. The age of this genus is estimated at about 2.3 to 2.4 million years with the beginning of the emergence of what we call “skilled man”.

The genus Homo was distinguished by several characteristics, for example, the size of its skull was large, allowing for a large space for the brain. Also, this genus was able to walk on only two limbs with hands and legs longer than usual, and was able to build complex tools, and is considered a "Neanderthal man." One of the species classified within the "Homo" or Homo genus.

Well, Bapu's work begins with Neanderthals.

For a long period of time, studies of human evolution depended on analyzes of ancient bone remains and their phenotypic characteristics and examination of tools left by members of the human race. And they spread in a huge strip extending from southern Europe to central Asia.

According to the fossils that we found, they are shorter than us, with relatively full bodies and a wider chest.

At some point, it became clear that genetic analysis was required to more precisely examine the nature of hominins such as Neanderthals.

It started with Alan Wilson, who worked as a professor of biochemistry at the University of California, Berkeley, where he studied how modern humans relate to one another by studying so-called mitochondrial DNA (mtDNA) from African and non-African populations, his results suggesting a common origin in Africa. for all modern humans, which was the foundational beginning of what we now know as the “Out of Africa” theory.

Left: Neanderthals, right: Homo sapiens.

(Social Media)

A straw hunter in a straw mountain

In 1987, Babu moved on to work on ancient (ancient human) DNA as a postdoctoral fellow in Alan Wilson's lab, but Babu wanted to stretch the lines straight and work on samples of non-modern humans, at first it was nearly impossible. At the time, researchers agreed that it is never possible to extract DNA from samples whose age exceeds the 40,000-year barrier.

There is no doubt that this sample will be - in addition to severe damage over time - mixed with the DNA of millions of species of bacteria, and other organisms such as humans and others who passed this or that cave, we are talking here about a healthy sample in which it occupies a space of much less than 1% The rest is just pollution that can spoil the experience, it's like looking for a straw in a mountain of straw!

At that point let's talk about DNA, which is simply the codes of life that you inherit from your parents. Every cell in your body (one of which is measured in millionths of a meter) contains a copy of your DNA. Imagine your body like a movie you watch on your computer screen, I got it from a friend's "flash memory" of yours, this movie originally consisted of a lot of information encoded on this "flash memory".

Our human cells also contain a long strand of chemical units representing DNA that carries information about almost everything, the color of your hair, the color of your eyes, the length of your bones, down to the most minute molecular morphology and chemical reactions in our bodies.

The same is true for Neanderthals or any other being.

In 1990, Papau moved to work at the University of Munich, and there he obtained the remains of a Neanderthal humeral bone from the Rheinische Museum in Bonn, Germany. The bone contained mitochondrial DNA, and he began his research to extract traces of Neanderthal DNA.

Experiments were conducted to ensure the accuracy of the results, then experiments were repeated on a new piece of bone, and a piece of Neanderthal bone was also sent to "Mark Stoneking" in the Laboratory of Anthropological Genetics at the American University of Pennsylvania to carry out the experiment in an independent laboratory, the experiment was repeated in more than one place and in more than one way , then finally we come to the final result;

The Neanderthal genome has been prepared, and the genome is a sheet of an organism's genetic content, or a book of its traits.

But there is a problem, mitochondrial DNA is only found in the mitochondria, which is one of the cell organelles responsible for giving our cells energy, and despite its ease of use for scientists, it gives only limited information about the organism, and here the challenge escalated because it is very difficult to devise techniques for purifying the DNA But in March 2010 he was able to discover a new species of hominid found in Denisova Cave, on Mount Altai in Siberia (Russia), all he found was the tip of a finger, but the DNA that was extracted from it confirmed that we are in front of a new species of humankind that we now know as "Denisovan", after the cave in which it was discovered.

The Great Journey

Years ago, during which Babu established a new science thanks to his successive research, "Paleogenomics", by revealing the genetic differences that distinguish all living humans from extinct hominins, now we know that "Neanderthals" and "Denisovans" are Our closest relatives as modern humans are from the genus Homo, and they lived together until 30-40 thousand years ago, and inhabited Eurasia (Europe and Asia), the Neanderthals in the west, and the Denisovans in the east, and in Africa our ancestors of the genus Homo sapiens inhabited, we now know from the last fossils that Found in Jebel Irhoud in Morocco that Homo sapiens humans lived here more than 300,000 years ago.

But the advanced research of Papo and his companions has drawn attention to something deeper and more important. When comparing the genomes of modern humans (Homo sapiens), Neanderthals and Denisovans, we find an interesting similarity, as the genomes of modern humans of European or Asian descent contain a proportion of 1-4%. of the Neanderthal genome, while the genome of modern humans of Southeast Asian or Western Pacific ancestry contains 1-6% of the Denisovan genome.

With the succession of data, scientists in this range, headed by Babu, suggested that there was intermarriage between humans, Neanderthals and Denisovans, and thus Babu refines the theory of exit from Africa, saying that 70,000 years ago when humans migrated from Africa to Europe and Asia, they mated with Neanderthals, and the sons of These matings, by extension, possess some of the DNA of this species.

On a later trip to Africa, humans transferred part of the Neanderthal trace to Africa, so there is a possibility that you will find in your genome - if you decide to analyze it one day - a trace of Neanderthals.

Now we know that the Neandertals were probably less intelligent than modern humans, but they were not a barbaric version of the ancestors of humans as researchers imagined decades ago, as successive research results appeared during the past decade saying that they were the first to set fire, and they were the first artists of the earth after a surprising discovery The scientific community in three Spanish caves for an abstract combination of geometric shapes, in addition to primitive attempts to draw some animals, and some studies suggested that they were the first to bury the dead.

Read more: Neanderthals in Iraq... How did hominins bury their dead?

And in a study issued in 2018, it turned out to be even more complicated than that, Svant participated in the study that found a fossil of a thirteen-year-old girl whose DNA is exactly the same between Denisovans and Neanderthals, 50% of her DNA is Denisovans and the other 50% is Neanderthals, which means that That this girl was the daughter of the father and mother of both of the two species, was evidence of the intermarriage that took place between the sons of Neanderthals and the sons of Denisovans.

Read also: Cave Girl.. Non-human origins reveal human history

Himalayan kings

Besides, Babu's work has provided amazing examples of ancient genetic variants that affect the physiology of modern humans and it is a highly dynamic field of research today that affects the development of medicine as a whole. One very interesting example, the first of which concerns the inhabitants of the Tibetan Plateau.

In 2010, an international team of researchers found that some Tibetans have changes in several genes, which help them deal more effectively with low levels of oxygen, and thus live smoothly in higher regions, and ascend to the summit of Everest with much less difficulty than those faced by the rest of humanity. .

These genetic changes were found in 87% of Tibetans.

These genetic changes were so remarkable that scientists conducted a more in-depth examination, specifically for a gene called "EPAS1". The results appeared in 2014 in the journal Nature to say that the Tibetans apparently benefited from a genetic gift that came to them tens of thousands of years ago when Homo sapiens interbred with the Denisovans. This particular gene is known to help regulate how the body responds to low levels of oxygen, it's also called the "super athlete gene" because we know that some people who have some special copies of this gene do better in athletics.

In addition to this type of genes, this range revealed complex relationships to infection with some diseases, such as diabetes and genes inherited by humans with Neanderthals. Sensitivity to the emerging corona virus, and by extension the severity of symptoms up to death, and genes inherited by humans from Neanderthals as well.

explorers

But there is no doubt that the most important thing that Babu and his companions presented in this context are successful attempts to answer a question that preoccupies the minds of many scholars as well as non-scholars, which is “How did we become what we are?” Over hundreds of thousands of years, how did we adapt?

How did human beings develop and their ways of life diversified and flourished?

Babu's attempts answered part of the question regarding the course of humans over the past 70,000 years.

But the full answer to this question still needs more research, especially if we decide to examine the continent of Africa, where scientists' understanding of the genome of human beings from the hominins who lived there, and before them, is still very weak, even though it is the continent that contains the largest Degree of genetic diversity throughout the planet.

The continent's climatic conditions require the development of new, more accurate and powerful tools, Babu and his comrades are on the road to this now.

What Babu has accomplished remains a wonderful example of the accuracy of science. From very small and almost completely damaged samples of organisms that lived 30-40 thousand years ago, we are able to obtain information that can fill entire volumes. The oldest sample that scientists have been able to analyze their DNA until now was For a horse that is 700-800 thousand years old, can you imagine that?!

As for the Neanderthals, the oldest specimens are more than 400,000 years old!

The universe arose - as we imagine - from a big explosion that occurred 13.8 billion years ago, it grew slowly and its temperatures decreased with the expansion of space-time until the first galaxies appeared after a relatively short period, about a billion years only.

After that, the conditions allowed the planets to form and revolve around the stars, and then, 3.8-4.1 billion years ago, the first images of life appeared on our planet in a way that still calls us to wonder, before the wise man existed only about 300,000 years ago, and then science appears in its modern form several hundred years ago. Only a few years ago, we use it to probe the depths of all that majestic cosmic history.

Carl Sagan once said:

“We are the universe and it is trying to discover itself.”

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Sources

  • Scientific Background Discoveries concerning the genomes of extinct hominins and human evolution