The 2022 Nobel Prize will be awarded this week in Stockholm, Sweden. Swedish geneticist Svante Pääbo has won the 2022 Nobel Prize in Medicine for research into human evolution. I’m sure many people are asking what evolution has to do with medicine. And, the answer is “quite a lot”!
The famous Ukrainian geneticist Theodosius Dobzhansky once said that “nothing in biology can be understood except in the light of evolution.” Medicine is based on human biology, and human biology cannot be understood without an evolutionary perspective. Perhaps the best example of this is the ongoing evolution of new variants of the current COVID-19. These new forms (for example, BA.5) continue to arise through Darwin’s principles of natural selection. That is, new forms arise through continuous mutation, and those forms that are more effective in individuals increase in frequency of person-to-person transmission. Understanding the evolution of such new variants is important for developing effective public health programs to reduce the likelihood of such new variants emerging.
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The committee awarded Pabo the prize “for discoveries concerning the genomes of extinct hominins and human evolution”. In 2010, Pääbo and his research team published DNA sequences from a 40,000-year-old Neanderthal specimen. These sequences revealed that Neanderthal DNA survives today, scattered throughout the modern human genome.
Modern humans and Neanderthals coexisted in Europe about 50,000 years ago after modern humans left Africa. The question of whether Neanderthals interacted with and interbred with our ancestors has been speculated by both scientists and novelists. Pabo’s work revealed that Neanderthals interbred with modern humans. The genomes of present-day human populations from outside Africa are composed of 1-4% Neanderthal-derived sequences. The human genome is about 3 billion base pairs; This means that 30 to 120 million DNA base-pairs from Neanderthals are present in most humans today.
Most of the Neanderthal DNA in our genome has no detectable effect. However, some segments of Neanderthal DNA have potentially important medical implications. For example, parts of Neanderthal DNA have genetic factors underlying both the susceptibility to infection with Covid-19 and the severity of such infection.
Evolution and genomics are becoming important tools in medicine. Cancer tumors are composed of collections of cells with varying degrees of resistance to particular chemical treatments. Using a single drug to treat cancer results in natural selection that causes the growth of cells that are more resistant to treatment. Current cancer treatments employ evolutionary principles that use multiple drugs to reduce the likelihood of developing resistance to treatment.
In addition, the use of genomic information is now called “personalized medicine” which involves using a person’s genomic information to design their clinical care. There is a lot of genetic variation between individuals in how they respond to different drugs. For some conditions, an individual’s genomic information can be used to help diagnose disease, predict outcomes, and guide treatment.
Fred Allendorf Regents Professor of Biology Emeritus at the University of Montana and writes about current science developments for Missoulians.