Coronavirus mutates, but is it evolution?

Coronavirus mutates, but is it evolution?

We keep reading how the coronavirus is transformed and mutated, and evolutionary believers of course believe that this is evolution. Let's take a closer look at what this is all about.

Coronavirus belongs to the so-called RNA viruses, i.e. it has a single-stranded RNA sequence that it tries to replicate by hijacking mechanisms of the host cell. It thus hijackes the most important cellular mechanisms involved in RNA processing to produce its own protein for enhanced replication.

Transmission between organisms and viral replication burden this RNA sequence causing mistakes to its sequence. In general, RNA viruses mutate quite rapidly and also weaken and even disappear rapidly, but SARS-coV-2 is more resistant to normal coronaviruses because of its ability to produce enzyme called exoribonuclease for RNA strand proofreading mechanism, which acts as a repair enzyme for RNA produced by the virus. Thus, when normal coronaviruses experience about half a dozen mutations per every replication event, the SARS-coV-2 mutation rate is only about 2 mutations per every human-to-human transmission event. Researchers have found that if exoribonuclease is modified or blocked, the virus will mutate very quickly and the infected person will recover very quickly. Here could be one key to developing a working vaccine.

https://www.nature.com/articles/nrmicro3125

Excerpt: "The polymerase of RNA viruses lacks the proofreading capacity found in the polymerase of DNA viruses, leading to high error rates and low replicative fidelity. Although the high mutation rate of RNA viruses enables them to readily adapt to environmental changes, they also risk 'lethal mutagenesis' when accumulating mutations corrupt essential functions. Here, Smith et al. reveal that, in the case of severe acute respiratory syndrome coronavirus (SARS-CoV), an exoribonuclease domain (ExoN) in non-structural protein 14 provides proofreading activity that protects the virus from mutagenesis.
 

Previous work in coronaviruses, the largest RNA viruses, had shown that ExoN deletion leads to reduced replicative fidelity and attenuation of virulence. Thus, Smith et al. speculated that ExoN is a proofreading enzyme. To test this hypothesis, they infected cells with wild-type (ExoN+) or ExoN-deleted (ExoN−) SARS-CoV in the presence of the mutagenic pyrimidine analogue 5-fluorouracil (5-FU). Indeed, loss of ExoN sensitized the virus to 5-FU, as shown by a 160-fold reduction in viral replication for ExoN− SARS-CoV compared with ExoN+ SARS-CoV. Furthermore, genome sequencing of viral populations after 5-FU treatment revealed that ExoN− SARS-CoV harboured 3,648 mutations, whereas ExoN+ SARS-CoV accumulated only 259 mutations. Of these mutations, 3,304 and 197 were U-to-C and A-to-G transitions, respectively, which are characteristic for nucleotide mismatches caused by the incorporation of 5-FU metabolites. Taken together, these results show that ExoN proofreading protects SARS-CoV from the deleterious effects of mutagens, such as 5-FU."

My comment: The virus can also be modified at the epigenetic level. More than 150 different types of RNA epigenetic markers are known. Even a small change at this level can cause significant changes in viral behavior, replication rate and susceptibility to spread. It is certain, however, that in any case, this serious coronavirus will also experience RNA base sequence mutations, i.e. errors, and over time will disappear or fall into harmless viruses. Evolution is still not happening, as modification and replication lead to corruption of biological information just as with organisms in nature. Don't get lost my friends.