On October 3, 2022, Swedish Scientist (Svante Pääbo)http://www.http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/http://www.svante Pääbo.com/httpp.com/httpppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp
Human beings are always interested in their origins.
Where do we Homo sapiens come from?
What is the relationship between our Homo sapiens and the ancient humans before?
What makes us Homo sapiens different from other ancient humans?
Svante Pääbo (Svante Pääbo) Through his pioneering research, accomplished a seemingly impossible thing - genetically sequencing of human close relatives , who have been extinct for tens of thousands of years. He also discovered a previously unknown ancient human species - Denisovan . More importantly, his research confirms that after humans left Africa about 70,000 years ago, gene flow occurred between Neanderthals and Denisovans, and some genes of these extinct ancient human species are still in modern humans. These ancient genes affect our immune response to infection, our ability to adapt to high-altitude environments, and even our fertility.
These pioneering studies have produced a new discipline - Paleogenomics (Paleogenomics) . lays the foundation for exploring what makes us unique humans by revealing the genetic differences between existing humans and extinct ancient human species.
Svante Pääbo is 67 years old this year. His father Sune Bergstrom won the 1982 Nobel Prize in Physiology or Medicine for prostaglandin-related research
Although the bones of Neanderthal were first discovered in the mid-19th century, only by unblocking their DNA can scientists fully understand the connection between the two species of Neanderthals and modern humans.
Svante Pääbo (Svante Pääbo) was the first to develop new technology, allowing researchers to compare the genomes of modern human (Homosapogon) with other ancient human (Neanderthal, Denisovan) .
Chairman of the Nobel Committee Anna Wedell said that Svanter Parbo's pioneering discovery provides important new knowledge for the evolutionary history of mankind.
Where do we come from?
The origin of our human beings and what makes us unique are these two questions that have bothered human beings since ancient times. Paleontology and archaeology provide evidence that modern human (Homo SapiensHomo sapiens) first appeared in Africa about 300,000 years ago. Our known close relatives, Neanderthals (Homo neanderthalens), developed outside Africa. Neanderthals began to live in Europe and West Asia about 400,000 years ago, and they became extinct about 300,000 years ago.
About 70,000 years ago, the Homo sapiens migrated from Africa to the Middle East and began to migrate to the rest of the world from there. Therefore, Homo sapiens and Neanderthals coexisted for tens of thousands of years in many areas of Eurasia.
In the late 1990s, the Human Genome Project sketch was completed, and almost the entire human genome was sequenced. This great achievement provided conditions for the subsequent study of genetic relations between different human species.
However, studying the relationship between Homo sapiens and the extinct Neanderthals requires sequencing of genomic DNA recovered from ancient specimens.
An impossible task
Early in his scientific research career, Svante Pääbo (Svante Pääbo) was fascinated by the possibility of using modern genetic methods to study Neanderthal DNA. However, he soon realized the extreme challenges facing the technology, because over time, DNA undergoes chemical modification and degradation into short fragments. Thousands of years later, only a small amount of DNA will remain, and most of the remaining ones will be contaminated by bacteria and human DNA.
As a postdoctoral fellow at Allan Wilson, a pioneer in evolutionary biology, Svante Pääbo began developing methods to study Neanderthal DNA, an effort that lasted for decades.
In 1990, Svante Pääbo (Svante Pääbo) was admitted as a professor at University of Munich, where he continued to work in ancient DNA. At this time, he decided to analyze Neanderthal mitochondrial DNA . mitochondrial genome is very small and contains only a small part of the cell's genetic information, but there are thousands of mitochondrial in one cell, which increases the chance of success.
Through improved methods, he successfully detected a mitochondrial DNA sequence from a Neanderthal bone 40,000 years ago. This is the first human being to obtain the genetic sequence of an extinct close relative. Comparisons with modern humans and chimpanzees show that Neanderthals are genetically different.
for Neanderthal genome sequencing
mitochondrial genome is too small, and analysis can only provide limited information. Therefore, Svante Pääbo (Svante Pääbo) posed a huge challenge for Neanderthal nuclear genome sequencing. He founded the Max Planck Institute for Evolutionary Anthropology and began to improve methods for isolating and analyzing DNA from remains of ancient bones.
With the advancement of technology and the joint efforts of key collaborators, Svante Pääbo completed this seemingly impossible task and published the first Neanderthal genome sequence in 2010. Genome sequence comparison analysis shows that the recent common ancestors of Neanderthals and Homo sapiens lived about 800,000 years ago, and since then, Neanderthals and Homo sapiens developed into two independent species.
They also investigated the relationship between Neanderthals and modern people from different parts of the world. Comparative analysis showed that Neanderthal DNA sequences were more similar to those of contemporaries from Europe or Asia, rather than those from Africa. This means that Neanderthals and Homo sapiens have intermarriage in coexistence, resulting in gene flow. Among modern humans with European or Asian descent, about 1-4% of the genome comes from Neanderthals.
Denisovans
In 2008, a fragment of phalanx from 40,000 years ago was found in the Denisovan cave in the southern part of Siberia . The bone contains very well-preserved DNA, which was sequenced by the team of Svante Pääbo. The results caused a sensation: This DNA sequence is unique compared to all known DNA sequences of Neanderthal and modern humans. Therefore, this is a new ancient human species that was unknown before - Denisovan . The discovery of Denisovan phalanx fragments
was a sensation. Subsequent studies showed that the Minneanderthals and Denisovans were sister groups separated from each other about 600,000 years ago. And up to 6% of the Denisovan genes were found in modern humans in Asia and Southeast Asia, indicating that the Denisovans intermarried with humans there, resulting in gene flow.
These findings gave us a new understanding of the evolutionary history of . When modern human (Homosapogon) walked out of Africa, there were at least two extinct ancient human species in the Eurasian continent, the Neanderthals living in the western Eurasian continent and the Denisovans living in the eastern Eurasian continent. During the process of moving to the world after Homo sapiens left Africa, they met and intermarried with Neanderthals and Denisovans, gaining genes that improved Homo sapiens' chances of survival in a new environment. For example, humans in the Qinghai-Tibet Plateau area of my country share a group of genes that help adapt to high altitude environments.
creates a new discipline - paleogenomics
Through pioneering research, Svante Pääbo (Svante Pääbo) has established a new scientific discipline - paleogenomics (Paleogenomics) .
After the initial discovery, his team completed the analysis of several genome sequences of the extinct ancient humans. These findings have built a unique resource that has been widely used by the scientific community to better understand human evolution and migration.
Thanks to Svante Pääbo for his discovery, let us understand that comes from the extinct close relatives of humans (Neanderthals, Denisovans) , which is still affecting the physiological functions of today's humans.
For example, Denisovan EPAS1 gene, it gives the advantage of survival in high altitude areas, which is very common among Tibetans in China today.
In September 2020, Svante Pääbo (Svante Pääbo) et al. published a paper in Nature stating that the risk of developing severe illness after 【2】, , , is caused by the genomic fragment of about 50kb-long length inherited from Neanderthal , which is the highest in South Asia and Europe, while it is almost non-existent genomic fragments in East Asia and Africa.
In September 2020, Svante Pääbo (Svante Pääbo) et al. published a paper in the journal Molecular Biology and Evolution stating that 【3】, One-third of European women inherited the progesterone receptor gene from Neanderthals - a genetic variant related to improved fertility, reduced bleeding in early pregnancy and reduced miscarriage.
In July 2020, Svante Pääbo (Svante Pääbo) et al. published a paper in the journal Current Biology pointing out that 【4】, The sensitivity of modern humans to pain was inherited from Neanderthals, which also explains why European and American people are more sensitive to pain.
What makes us unique human beings?
Modern human (Homosapiens) is characterized by its unique ability to create complex cultures, advanced innovations and concrete art , as well as its ability to travel through open waters and migrate to all parts of the world.
Neanderthals also live a group life with huge brains. They also use tools, but for hundreds of thousands of years, they have developed very little about these tools.
Modern human skull (left) and Neanderthal skull (right)
Genetic differences between modern human (Homosapiens) and these extinct close relatives have been unknown until Svante Pääbo (Svante Pääbo) did these groundbreaking work that allowed us to study and explore the differences between these extinct ancient and modern humans at the genome level.
For example, on September 9, 2022, a paper published on Science pointed out that the difference between [5], a key protein - TKTL1, gives us humans a significant advantage over Neanderthals, increasing the production of brain nerve cells , which may be the basis of cognitive differences between modern humans and other extinct ancient humans.
On February 12, 2021, a paper published in the journal Science found that 【6】, Modern human , Neanderthal and Denisovan , an important differential gene of the existence of two extinct ancient humans - NOVA1. Through CRISPR-Cas9 gene editing , the NOVA1 gene version of ancient humans was introduced into human pluripotent stem cells and cultured into " brain organoid ". It was found that the neurodevelopment , cell proliferation , and the splicing of synaptic junction related genes of were significantly changed.
results show that after humans and Neanderthals were "separated", the NOVA1 gene has formed a stable new version in modern humans, which is likely to have a functional impact on the evolution of our human species .
At present, a large number of studies are exploring the impact of these genomic differences, and will ultimately help us explain why we can be unique humans.
Reference :
1.https://www.nobelprize.org/prizes/medicine/2022/advanced-information/
2.https://www.nature.com/articles/s41586-020-2818-3
3.https://doi .org/10.1093/molbev/msaa119
4.https://doi.org/10.1016/j.cub.2020.06.045
5.https://www.science.org/doi/10.1126/science.abl6422
6.https://science.sciencemag.org/content/371/6530/eaax2537
