Have you ever heard about the Denisovan? They were a now-extinct species within the genus Homo, the same one which our species H. sapiens is part of (actually ours is the only living species in genus Homo nowadays). Well, the discovery of this hominin species is one of the results of Svante Pääbo's research. He discovered it by sequencing the DNA from a forty-thousand-year old bone fragment found in the Denisova cave (hence, the name of the species), in Siberia.
Surely, you have heard about the Neanderthals, instead. This is another species within our genus (whose “full name” is Homo neanderthalensis), known since the 1850s. What you might not know is that Pääbo is the leader of the group the sequenced the entire genome of this species too.
These two results are the main reasons (but not the only ones) why the 2022 Nobel Prize in Physiology and Medicine has been awarded to Svante Pääbo. Other implications of Pääbo’s research are the ascertainment of the admixture of our species with both Neanderthals and Denisovans occurred in Eurasia around fifty thousand years ago, as testified by portions of their genomes in present-day human genomes from these geographical regions. This is a striking implication of Svante Pääbo’s research, which raised interest and curiosity in the larger public as well. Another worth mentioning point is that, to achieve these results, Pääbo developed complex technologies and methods in order to extract and process ancient DNA as contained in fossil bones tens of thousands years old. This is how he actually founded a brand new scientific discipline, now-called “paleogenomics”, i.e., the study of ancient genomes. It might struck the reader that such impressive scientific discoveries and developments was triggered by what might appear, at first sight, an almost childish curiosity of the young geneticist Svante Pääbo while he was doing his PhD on unrelated topics: sequencing the DNA of an Egyptian mummy (a childish curiosity that, anyway, ended up in a Nature paper in 1985 …). Since then, Pääbo’s research brought about impressive findings, and the implications of his work are not limited to our past evolutionary history, as they disclose promising perspectives in medicine as well, as far as both gene-based disease and viral epidemies are concerned – as envisaged by Dulbecco (according to his paper included in this special issue) already in 1986. The reader may find insights into all this in Pääbo’s Nobel Lecture we propose in this special issue.
Pääbo’s research, besides the “technical” merits hinted at here above, also has huge anthropological, interdisciplinary implications. Specifically it has implications for a key topic in “Science and Religion” (the field which this whole website engages in): the issue of human uniqueness. Pääbo explicitly states, in many interviews and declarations (not only after having been awarded the Nobel Prize), that is research opens up interesting widows over the issue of how and why present-day human beings are unique. Well, one might think that such uniqueness (as emphasized by a geneticist) should be grounded in our unique genome, different from that of all other species, extant and extinct. Of course, but this hold true, indeed, for every biological species. What is to be emphasized is that such uniqueness is to be found – also according to geneticist Pääbo – in our sociality and culture.
And so: genes or culture? Questions like the one about human uniqueness are complex ones and, as such, do require articulate answers. Many current developments in archeology, physical anthropology, as well as evolutionary biology suggest that answering the question about “what made as humans” involves many different topics. Culture and cultural evolution, as well as how human cognition emerged and developed along our natural history, are part and parcel of the matter, and should not be considered as mere epiphenomena or by-products of our genetic evolution. Pääbo’s research unveils (and will allow future scientists to unveil further) many interesting details of our genome and about how it acquired its current composition. However, these results does not imply that gene changes always and necessarily precede changes in cognition and culture. Sometimes, genetic changes are the consequences of our cognitive and cultural behavior. To put it directly, if our ancestors H. sapiens of more the fifty thousands years ago where able to colonize the whole Eurasia and to have exchanges with other hominin species already present in these regions, this means that their culture and cognition were already developed enough to do that.
More generally, mechanisms of cognitive and cultural evolution might not be entirely reducible – as effects to their causes – to mechanisms of genetic evolution. We need a bigger picture. This is the reason why in this special issue we gather together, along with a presentation of Pääbo’s achievements in genetics, pages from contemporary scientists able to offer insights to build such a bigger picture, considering how the “mental capacity” of the human being might not only be the direct consequence of genetic evolution and natural selection (the paper by Dobzhansky and Ashley Montagu), and how evolution can be applied to culture (the chapter by Renfrew). Moreover, we also complement such scientific perspectives with contributions about how “mind” can be understood as emerging from “matter” (Polkinghorne’s paper) and on how theology can address the issue of biological evolution (Rahner’s excerpt).
Within this bigger picture, of course, genetic data such as those Pääbo definitely contributed to the field will be key in the huge effort of understanding our origins and what makes us humans, provided that they are not uncritically regarded as the main causes of the process but (often) also as the ascertainable consequences of genuinely cognitive and cultural processes that characterized our history.
DISF Center Vice-Director