Influenza undergoes recombination seemingly exclusively through reassortment whereas betacoronaviridae undergoes homologous recombination -- but to think of the

Influenza undergoes recombination seemingly exclusively through reassortment whereas betacoronaviridae undergoes homologous recombination -- but to think of the latter as much less effective at producing genetic diversity may be incorrect. > In fact, there is evidence of at least seven potential regions of recombination in the SARS-CoV genome in the replicase- and Spike-coding regions, with possible recombination partners that include porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), bovine coronavirus (BCoV), HCoV-229E, MHV, and IBV [1] > Unlike other viruses that have emerged in the past two decades, coronaviruses are highly recombinogenic. ... For coronaviruses, however, recombination means that small genomic subregions can have independent origins, identifiable if sufficient sampling has been done in the animal reservoirs that support the endemic circulation, co-infection and recombination that appear to be common. [2] > Recombination seems to be rampant in HCoV-OC43 viruses and contributed to originate the A to E viral genotypes, as well as viruses that do not belong to these major genotypes. [3] Unfortunately, nature doesn't "design" anything, it's just the consequence of natural selection and fitness of new generations. While the mutation rate might low compared to influenza, the mutation rate is very high compared to something like a prokaryote, enough so that there's an article entitled "Why are RNA virus mutation rates so damn high?" We've already seen a gain of function mutation creating enhanced infectivity and a recombination event involving ferrets, so it's not a stretch that we might see a new more of this in the future. Whether or not it will impact the toxicity of the virus or whether or not its susceptible to a vaccine is up in the air, but once an effective vaccine exists strong selective pressure will be placed on versions of the viruses that evade it. [1] https://jvi.asm.org/content/84/7/3134 https://jvi.asm.org/content/84/7/3134 [2] https://www.nature.com/articles/s41564-020-0771-4 https://www.nature.com/articles/s41564-020-0771-4 [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7111218/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7111218/