When one could have wished for something – a moderate wish within the realm of realistic possibilities – then maybe that Sars-CoV-2 behaves evolutionarily similar to what we know from crocodiles. These reptiles have hardly changed in terms of their basic body structure since the early Jurassic 200 million years ago, and that with a very clear wealth of variants: There are only 24 species. Ridiculously few, then, compared to dinosaurs or the scaled lizards living today, which each come in around 10,000 species.
A study in “Communications Biology” has recently examined the background to this evolutionary constancy on the basis of a phylogenetic model: According to this, crocodiles have developed very little over long periods of time, measured by their body size. Apparently they had reached such an efficient and versatile development status that major adjustments were only necessary if they were really necessary due to changes in their environment, e.g. climatic type.
For the crocodiles and our getting along with them, that’s probably good news. Sars-CoV-2 was also initially not thought to be excessively susceptible to mutations: half the rate of change as the flu virus, a quarter as strong as the HI virus, these were the experts’ assessments based on genetic sequencing data. “As long as almost everyone on the planet is susceptible, there is probably little evolutionary pressure to adapt to the virus to develop better transferability,” read “Nature” in September. In the meantime we unfortunately know better and have to realize that the virus has probably wasted its chance to become the crocodile in the virus spectrum.
There is still speculation about the origins of the mutations. But one thing is clear: where there are many infected people, there are many mutations. And in fact, one can hardly imagine which crocodile monsters would populate the earth today if there had been anywhere near as many crocodiles as Sars-CoV-2 particles in the history of the earth.