Dr. Svante Pääbo「An Ancient DNA View of Human Origins」
JapanPrize・31 minutes read
Modern humans originated in Africa, spreading out around 70 thousand years ago and interacting with Neanderthals and Denisovans, leading to genetic contributions impacting modern humans. Research on Neanderthal DNA reveals variants affecting health outcomes, including a progesterone receptor variant linked to pregnancy complications and a risk factor for severe illness from viruses, with global implications during the pandemic.
Insights
- Genetic studies have revealed that modern humans carry about 2% Neanderthal DNA, showing interactions and interbreeding between the two groups as they spread globally.
- Neanderthal genetic variants impact modern humans, with a progesterone receptor variant linked to both premature births and protection against miscarriages, highlighting the complex effects of ancient DNA on present-day health outcomes.
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Recent questions
How did modern humans originate?
In Africa 2-4 hundred thousand years ago, spreading globally.
What is the relationship between Neanderthals and modern humans?
Neanderthals are the closest evolutionary relatives to present-day humans.
What is the significance of Neanderthal DNA in modern humans?
Neanderthal DNA impacts modern humans, influencing traits and health.
How do Neanderthal variants affect health outcomes?
Neanderthal variants can influence health outcomes, such as preterm birth.
What insights do genetic studies provide about Neanderthals and Denisovans?
Genetic studies reveal origins, interactions, and impacts of Neanderthals and Denisovans.
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Summary
00:00
"Neanderthal DNA Impact on Modern Humans"
- Modern humans originated in Africa around 2 to 4 hundred thousand years ago, spreading out of Africa and the Middle East around 70 thousand years ago.
- Neanderthals and other human forms coexisted with modern humans, with Neanderthals being the closest evolutionary relatives to present-day humans.
- Research focused on retrieving DNA from ancient remains, facing challenges like contamination and degradation of DNA over time.
- Techniques have been developed to retrieve short DNA pieces from various organic remains, leading to the sequencing of high-quality genomes of at least three Neanderthals.
- Comparison of Neanderthal genomes with modern humans revealed that present-day individuals carry about 2% Neanderthal DNA, varying in segments among different individuals.
- Denisovans, another human group, were discovered in Siberia, with their DNA contributing to present-day Asians and Oceanians.
- The origins of Neanderthals and Denisovans trace back to Africa, evolving into distinct groups in Western and Eastern Eurasia.
- Modern humans interacted with Neanderthals and Denisovans, mixing with them multiple times as they spread across the globe.
- Genetic studies have identified variants from Neanderthals that impact modern humans, such as a progesterone receptor variant associated with preterm birth.
- Tracking the frequency of Neanderthal variants in ancient genomes allows researchers to understand the impact and evolution of these genetic contributions over time.
20:03
Neanderthal Genetic Variants Impact Health Outcomes
- Around 5-7 thousand years ago, a variant associated with bleeding in early pregnancy, miscarriages, and fewer siblings was discovered in a cohort study of 400,000 individuals in the UK Biobank.
- The Neanderthal progesterone receptor variant linked to premature births but also protective against miscarriages, leading to a trade-off of saving pregnancies at the cost of early births.
- The Neanderthal variant of the progesterone receptor is more highly expressed, potentially explaining its effects in the uterus.
- Studies have shown that administering progesterone to women with previous miscarriages can reduce the risk of further miscarriages, aligning with the idea of increased progesterone effects being beneficial.
- A genetic risk factor for severe illness from viruses, including the current pandemic, was found on chromosome 3, with the risk variant originating from Neanderthals.
- The presence of this Neanderthal risk variant has led to over a million additional deaths globally during the pandemic, with varying frequencies across different regions.
- The Neanderthal variant on chromosome 3 increases the risk of severe illness from viruses but also decreases the risk of contracting HIV, showcasing the dual nature of genetic variants.
- Another Neanderthal-inherited variant on chromosome 12 has been protective against severe disease, highlighting the complexity of genetic influences on health outcomes.
- Modern humans exhibit unique genetic changes compared to Neanderthals, with approximately 30,000 nucleotide changes distinguishing the two groups.
- Specific changes in amino acids affecting proteins related to cell division, brain function, and brain development have been identified, shedding light on potential differences in modern human cognition and sociality.
39:52
Humanized Proteins in Mice Affect Metaphase
- Created mouse models with amino acid changes mimicking human and chimpanzee proteins in specific positions.
- Found that mice with all three humanized proteins had longer metaphase, similar to humans, while those with only two or one humanized protein also showed extended metaphase.
- Changing back to a Neanderthal-like state in human stem cells resulted in shorter metaphase and increased chromosome mis-segregation in brain cells, suggesting potential implications for brain development and function.
