Swedish Scientist Swante Pääbo won the 2022 Nobel Prize in Physiology or Medicine
On October 3, 2022, at around 17:30 Beijing time, the Nobel Prize Committee of Karolinska Medical College in Sweden announced that Swedish scientist Svante Pääbo won the 2022 Nobel Prize in Physiology or Medicine for his "discovery on the extinct ancient human genome and human evolution ".
Who am I? Where did I come from?
Since modern humans discovered that they exist in this world, they have been deeply trapped in the thought of "Who am I? Where am I from?" This basic philosophy is unable to extricate themselves.
Before the rise of science, the mainstream answer to this question in the West was: God created man and created everything.
In our country, although it is not as complete as the Western saying "God creates man", the answer is similar, that is, God creates man.
For example, Dong Zhongshu in "Spring and Autumn Flood" said that man was created by heaven - "Heaven is heaven", heaven is the great-grandfather of man, and the human body is longer than heaven - "Heaven is also the great-grandfather of man, and the reason why this person is the best like heaven. The human body is formed by the number of heaven."
The rise of science, especially paleontology and archaeology, made people realize that humans are still an animal in essence, gradually evolved from ancestors that share common to other organisms on the earth.
However, it is confusing why is human being the only "higher" animal on this planet with intelligence, using constantly improving tools, and creating splendid culture and art, with a huge difference from all other creatures?
Why are humans so different from the " ape " that has the closest genetic relationship in the biological evolution tree?
In other words, why are humans so unique on this planet?
This series of puzzles that have plagued mankind for thousands of years has finally come to a credible answer in the past decade. The answer is Swedish scientist, Swant Parbo, the winner of the 2022 Nobel Prize in Physiology or Medicine.
This scientist used the paleogenomics he founded to obtain a series of research results, not only giving reliable answers, but also compiling a charming and magnificent epic about the evolution and migration of modern humans for us.
So, rather than saying that Svanter Parbo is a scientist, he is more like a chanting poet armed with science.
Svanter Parbo, who is fascinated by Neanderthal DNA research, is an ancient human being living on the Eurasian continent. In the 19th century, the relatively complete skull and some other bones were discovered in a valley called Neanderthal in Germany, and was named Neanderthal.
Swant Parbo has been fascinated by the study of Neanderthal DNA since his student days.
However, at that time, this kind of research faced a technical challenge that seemed insurmountable, that is, over time, DNA would undergo chemical modifications and degrade into very short fragments. Thousands of years later, only traces of DNA fragments are left, and they will be contaminated by bacteria and contemporary human DNA.
How can we obtain more comprehensive information on Neanderthal DNA? Svanter Parbo began developing methods for Neanderthal DNA as a postdoctoral fellow as a pioneer in evolutionary biology, an effort that lasted for decades.
successfully sequenced Neanderthal mitochondrial DNA gene fragment
From 1990, Parbo was hired at the University of Munich in Germany and continued to engage in the research of ancient DNA.
We know that biological genetic material DNA exists in two parts of the cell: nucleus and mitochondrial . Nuclear DNA preserves most of the genetic information of organisms; relatively speaking, mitochondrial genome is very small, containing only a small part of the genetic information in the cell, with only a few thousand copies, making it relatively easier to study.
Therefore, Parbo decided to start by analyzing Neanderthal mitochondrial DNA.
The so-called hard work pays off. After unremitting efforts, Pabo finally successfully sequenced the gene sequence of the first regional fragment of Neanderthal mitochondrial DNA from a 40,000-year-old bone in human history for the first time.
analysis found that Neanderthals have genetic uniqueness compared to their contemporaries and chimpanzees.
Complete Neanderthal genome sequencing
Although it is an amazing achievement to successfully sequence Neanderthal mitochondrial DNA gene fragments, since the mitochondrial genome can only provide limited information, in order to solve the mystery, it is necessary to complete sequencing of Neanderthal nucleus genome.
Fortunately, Parbo received great support from the Max Planck Institute in Germany. In the new institute, Parbo and his team have steadily improved the methods for isolating and analyzing DNA from ancient skeletal remains. The new technology developed by the research team can enable DNA sequencing to be efficiently completed.
After multi-party collaboration and unremitting efforts, the Parbo team finally completed a seemingly impossible task and released the first Neanderthal genome sequence in 2010.
Discovered new extinct ancient human Denisovan
By using new DNA technology, the Pabo team published another sensational new discovery in in 2008, obtaining extremely well-preserved DNA from a phalanx fragment found in the Denisovan cave in southern Siberia .
By sequencing, the Pabo team discovered that it was a new extinct ancient human being different from the modern Homo sapiens and Neanderthals, and named the Denisovans after the discovery.
compiled the epic of modern human evolution and migration
Through a controlled study of the DNA sequence obtained from different regions of the world, the Pabo team drew an epic picture of modern human evolution and migration:
comparative analysis showed that the recent common ancestors of Neanderthals and modern Homo sapiens lived in Africa about 800,000 years ago.
Modern The ancestors of Homo sapiens first appeared about 300,000 years ago; Neanderthals walked out of Africa earlier, about 400,000 years ago. After leaving Africa, they mainly lived in Europe and West Asia until they became extinct about 300,000 years ago.
About 70,000 years ago, a group of modern Homo sapiens' ancestors migrated from Africa to the Middle East and from there to the rest of the world.
Therefore, Homo sapiens and Neanderthals coexisted for at least tens of thousands of years in most parts of Eurasian .
genome analysis found that the DNA sequence of Neanderthals had greater similarity to the gene sequences of contemporary people from Europe or Asia but not from Africa. This means that Neanderthals and Homo sapiens have undergone gene exchange-hybrid during their tens of thousands of years of coexistence. In modern humans with European or Asian descent, about 1-4% of the genome comes from Neanderthals. The analysis of the gene sequence of
also found that unlike Neanderthals who lived in Yesia, Europe, the Denisovans were mainly distributed in the eastern part of Eurasia. Moreover, there was a gene exchange between modern Homo sapiens and Denisovans. For example, people in Melanesia (an archipelago in the Pacific) and other parts of Southeast Asia carry up to 6% of Denisovan DNA.
In other words, after the ancestors of contemporary Homo sapiens left Africa, they coexisted and coexisted with the Neanderthals and Denisovans on the Eurasian continent for tens of thousands of years.
Moreover, our ancestors obtained genes that were crucial to survival through hybridization with these two extinct ancient humans.
For example, the EPAS1 gene from the Denisovans gives modern humans the advantage of survival in high altitude areas, which is common among contemporary Tibetans. Genes from Neanderthals affect our immune response to different types of microbial infections.
In the context of the COVID-19 pandemic, we will naturally have a deeper understanding and experience of the importance of immune response to biological survival.
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