Health

Nobel Prize for Medicine rewards findings on human evolution

STOCKHOLM (AP) — Swedish scientist Svante Paabo won the Nobel Prize in medicine on Monday for his discoveries of human evolution, which unlocked the secrets of Neanderthal DNA that helped understand what makes humans unique and provided new insights into our immune system, including our vulnerability to severe COVID-19.

The techniques Paabo used allowed the researchers to compare the genome of modern humans with those of other hominins: Denisovans and Neanderthals.

“Just like an archaeological dig to find out about the past, we carry out our own digs into the human genome,” Paabo told a news conference organized by the Max Planck Institute for Evolutionary Anthropology in Leipzig.

Although the first Neanderthal bones were discovered in the mid-19th century, only by understanding their DNA have scientists been able to fully understand the links between species.

That includes the time modern humans and Neanderthals split as a species, about 800,000 years ago.

“Surprisingly, Paabo and his team also found that gene flow from Neanderthals to homo sapiens had occurred, showing that they had children together during periods of coexistence,” said Anna Wedell, chair of the Nobel Committee.

This transfer of genes between hominid species affects how the immune system of modern humans reacts to infections, such as the coronavirus. People outside of Africa have between 1% and 2% Neanderthal genes. Neanderthals were never in Africa, so no direct contribution to people in sub-Saharan Africa is known.

Paabo and his team managed to extract DNA from a small finger bone fragment found in a cave in Siberia, leading to the recognition of a new species of hominid, known as Denisovan man.

Wedell called it a “sensational discovery” that showed that Neanderthals and Denisovans were sister groups that diverged about 600,000 years ago. Denisovan genes have been found in up to 6% of modern humans in Asia and Southeast Asia, indicating that interbreeding also occurred.

“By mixing with them after leaving Africa, Homo sapiens added sequences that improved their chances of survival in their new environment,” Wedell said. For example, Tibetans share a gene with Denisovans that helps them adapt to high altitudes.

Paabo, 67, said he was surprised to learn of his appointment, initially believing it to be a joke from colleagues or a call about his summer home in Sweden.

“I was having my last cup of tea to pick up my daughter, who was with her nanny who she spent the night with, and that’s when I got this call from Sweden,” she said in an interview with the awards website. Nobel. “I thought, ‘oh, the lawnmower broke or something.’”

He also pondered what would have happened if Neanderthals had survived another 40,000 years.

“Would we see even more racism against Neanderthals, because in a sense they really were different from us? Or would we see our place in the world very differently by having other forms of humans that look a lot like us, but are still different?” he wondered.

Dr. Eric Green, director of the National Human Genome Research Institute at the US National Institutes of Health, called it “a great day for genomics,” a relatively young field that was named in 1987.

The Human Genome Project, which ran from 1990 to 2003, “provided us with the first sequence of the human genome, and we’ve improved on that sequence ever since,” Green said.

When DNA from an ancient fossil is sequenced, only “trace amounts” are available, Green said. One of Paabo’s innovations was discovering methods to extract and preserve these small quantities.

Paabo’s team published the first draft of the Neanderthal genome in 2009, and sequenced more than 60% of the entire genome from a small bone sample, after dealing with decay and bacterial contamination.

“We should always be proud of having sequenced our genome. But the idea that we can go back in time and sequence the genome of something that is no longer living and something that is directly related to humans is really remarkable,” Green said.

Paabo said his team discovered during the pandemic that “the biggest risk factor for getting seriously ill and even dying when infected with the virus (SARS-CoV-2) has come to modern people from Neanderthals. So we and others are now intensively studying the Neanderthal version versus the modern protective version to try to understand what the functional difference would be.”

Paabo’s father, Sune Bergstrom, won the Nobel Prize in Medicine in 1982. It is the eighth time that the son or daughter of a laureate has also won a Nobel Prize.

The prize includes 10 million Swedish kronor (nearly $900,000) in cash and is presented on December 10 at a gala. The money comes from a fund left behind by the prize’s creator, Swedish inventor Alfred Nobel, who died in 1985.

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Ungar reported from Louisville, Kentucky.

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Associated Press journalists Frank Jordans, in Berlin; David Keyton, in Stockholm; and Maddie Burakoff in New York contributed to this report.

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The Associated Press receives support for its health and science coverage from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for the content.

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