Catherine Jessus, former director of the French CNRS’s Institute of Biological Sciences, anticipating the launch of France’s Biology Year, has some interesting (non-flapdoodle) things to say about biology, answering questions:
Why do you think we should focus on the drivers of evolution in the coming decades?
C. J.: It was long thought that new species were created through point mutations in genes. But in fact, this is just one of many ways in which new organisms can come about. The main source of innovation lies in the modification of large sections of genomes, which happens, for example, via the exchange and fusion of genomes between species. For instance, we now know that the first eukaryotic cell emerged through the combination of an archaeon and a bacterium. The bacterium that had entered the archaeon gradually lost its autonomy, allowing the formation of the membrane compartments, especially the mitochondria, that characterise eukaryotes. The same thing applies to the emergence of plants: a eukaryote entered into symbiosis with a bacterium that was able to use light to produce energy, giving rise to the first microalgae. And it was this same mechanism that explains why mammals have a placenta that enables the embryo to develop within the mother’s body.
You mean mammals are also the result of gene exchange?
C. J.: Exactly. The placenta developed thanks to the transfer of genes from a retrovirus to an animal that laid eggs. This particular retrovirus was able to produce proteins causing cell fusions, and it was these proteins that gave rise to the placenta. Without this little retrovirus, we’d still be laying eggs! Examples like these demonstrate the importance of the exchange of genetic material between living beings, something that was long neglected.Laure Cailloce, “The new frontiers of the living world” at CNRS News (November 7, 2021)
It’s probably not anywhere near as simple and certain as Catherine Jessus is making out. Viruses don’t likely do enough to create placentas. But the main point is, this definitely isn’t yer old biology teacher’s Split-the-Desk Rant for Darwin!!! Stay tuned.