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So much of what we know about our story we owe it to him. And when we talk about our story we refer to that of the our species. Actually the recent graduate (at home) Nobel prize for Medicine and Physiology 2022the Swedish biologist Svante Pääbo, shed light on the history not only of our species, but of a large part of the family, discovering new members and the relationships that bound them. A nobel that rewardsanthropology therefore, but which even earlier rewards the genetics: because without the ability to read our DNA and that of our relatives, which has been improving over the last thirty years, relationships and inheritances in the family would still have remained rather blurry.
Of Svante Pääbo – born in 1955, already winner of the Breakthrough Prize – on the pages of Wired we have talked many times. And it could not have been otherwise, because the Swedish biologist is in fact considered the father of paleogenomics. We owe the discovery and characterization of several to him and to his research groups fossils, very often through the reconstruction of family portraits. This is the case, for example, of the relatively recent discovery of the direct heir of theNeanderthal man and Denisova’s Homoparticularly curious considering that even the parents had been so to speak one discovery from Pääbo .
The problem of the archaic DNA
L’Neanderthal man in fact it had been known for some time, about a century before the biologist came into the world. How remember today the experts of the Nobel Committee retracing the studies of the Swedish biologist, it was in fact 1856 when the remains of the most famous of our cousins were found in the homonymous German valley, and those fossils, like many others, for a long time they were “read” only through classical paleoanthropology analyzes, that is, based on the anatomical morphological characteristics and those of the context in which they were found. It would have been the job of Pääbo and other pioneers in the field – such as the New Zealand biologist Allan Wilson – to revolutionize the field, to the point of distorting it, or by demonstrating that starting from the archaic DNA it is possible to reconstruct the traces of our evolution. Provided that dna is available and properly stored.
In fact, in itself the possibility of analyzing the ancient dna is complex: over the millennia molecules fragment, change, degrade – especially in less than ideal conditions with temperatures high – and become contaminated with what is present in the environment, plants, animals and microorganisms. Added to this is the risk of contamination due to the work of researchers, especially in the past. Part of the results of Pääbo’s work is due to the development of biological material management techniques and tools that could minimize material contamination and compromise the interpretation of results, as well as the benefit of newly born molecular biology techniques, such as there PCR for the analysis of dna (which basically allows to amplify genetic sequences). Before mitochondrial – that is, the genetic material contained in mitochondriathe power plants of cells, present in greater quantities because each cell contains many – then more than that nuclearanalyzing the fossils of ancestors discovered in various parts of the world.
Denisova’s Neanderthal and Homo works
Early studies of Neanderthal mitochondrial DNA showed that they were a distinct population, probably originating from a small nucleus that had then expanded, and that had contributed little genetically to modern human populations. It would take advancements in the preparation and analysis techniques of the genome in the years to come, and therefore also the sequencing of the nuclear DNA material, to demonstrate instead that i Neanderthalwho had separated from Homo Sapiens probably 800,000 years ago, had indeed contributed to modern populations: today it is estimated that between 1 and 2% of genomes modern are of Neanderthal derivation. A legacy that dates back to the period in which the two populations coexisted in Eurasia. For a long time we talked about how we were all heirs of the Neanderthals with the exception of African populations, but recent studies have reshuffled the cards on the table, suggesting that none of the modern populations can be said to be excluded from this inheritance.
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