Nobel Prize in Physiology or Medicine for 2022 goes to Svante Paabo
Once again it’s the season of Nobel Prizes. More than the other categories, this year’s Nobel Prize for Physiology or Medicine has created a worldwide stir as the recipient did revolutionary work that will further help understand human evolution. The winner is none other than world renowned paleogeneticist (a scientist who study the genes of prehistoric creatures) and evolutionary anthropologist Svante Paabo. This Swedish-origin scientist also happens to be the director of Germany-based Max Planck Institute for Evolutionary Anthropology, one of the foremost anthropological research centres in the world.
Paabo received the Nobel Prize for Physiology or Medicine for 2022 for his pioneering work on the DNA of extinct humans and their ancestors. His contributions include identifying previously unknown variety of human who lived alongside Neanderthals as well as early modern man more than tens of thousands of years ago.
As some of you might know, it’s through the study of genomes (complete genetic information of an organism) that scientists understand human evolution. However, till date, sequencing the genome of Neanderthals (an extinct relative of present-day humans) was deemed as impossible. Now, it looks like, Paabo has finally accomplished the impossible alongside making another exemplary discovery of an earlier unknown hominin (an evolutionary group that includes both modern humans and their other prehistoric bipedal relatives such as the Neanderthals) called Denisovan (named after the site where the fossils were first traced in 2008, aka, Denisova Cave in southern Siberia). Interestingly, Denisovans are being regarded as the sister group to the Neanderthals.
In case you are confused, Paabo has done a unique sequencing thus helping us understand the genetic differences we share with our ancestors. Now, as you can imagine, most of the genetic material derived from fossils is fragile, while the DNAs discovered in the prehistoric bones are often highly degraded, or chemically modified, and at times even contaminated (when exposed to acidity of soil, high temperatures, microbes and other harsh conditions). As a result, scientists over the years have found it difficult to conduct their research, until today. In fact, it turns out that Paabo with persistent efforts of many years finally succeeded to develop a series of new and advanced techniques through computational analysis that made the impossible possible. He was able to extract, duplicate and even read the broken DNAs and ended up reconstructing the original genomic content, that too from 40000-year-old bones. Guess what he ended up doing in the process? He established a brand-new scientific discipline called paleogenomics.
Okay, now here comes the question, what exactly did Paabo’s study reveals. Turns out, he has found that present-day humans intermingled largely with Neanderthals and Denisovans, as even though the gene variants differ, they are definitely related to one another. In fact, this research sheds light on certain weird instances, such as why some people are better adapted to living at high altitudes or why some people have better immunity system, so on and so forth.
What’s interesting here is that, before Paabo’s discoveries and research, much of our knowledge regarding human evolution came from bone analysis and artifacts spread worldwide, such as the first set of Neanderthal bones traced in 1856. But just analysis of bones and artifacts couldn’t answer all evolutionary questions, such as how closely did modern humans mingle with Neanderthals. And now, thanks to the gene flow, we know they were very closely knit and even had interspecies children.
Not only that, Paabo also offered new insights on the divergence of these different human species by simply comparing their genomes. For instance, his estimation suggests that modern humans split from their prehistoric ancestors around 550,000 to 760,000 years ago, while the Neanderthals and Denisovans parted ways around 380,000 to 470,000 years ago. The mystery that still remains to be solved is why Denisovans disappeared around the same time modern Homo Sapiens emerged and what exactly impacted their co-existence.