Musings on Viruses and Evolution

A Primer on Coronavirus, Variants, Mutation and Evolution
One has to wonder how creationists can maintain their beliefs during a pandemic where the virus is clearly evolving to improve its ability to infect people and avoid immune system responses. It’s like watching Darwin in action every day. What sort of cognitive dissonance is necessary to believe in creationism while reading the headlines about COVID variants emerging all over the world?

Or maybe they don’t read the news to avoid being confronted by such inconvenient truths.

Although viruses evolve mostly through mutations of their genetic code (DNA or RNA in the case of COVID-19), it is still Darwin’s natural selection at work that determines which of these variants (or strains) survive. As noted in The Guardian, viral mutation and its partner, natural selection, are ongoing processes, not one-time events (emphasis added):

The virus has been mutating from the start. On average, a single Sars-CoV-2 virus accumulates two single-letter mutations a month. The influenza virus mutates at about twice this rate. Many of the mutations that happened early on helped the coronavirus adapt to humans. One of the first mutations to go global is known as D614G, or Doug for short. This mutation arose early in the pandemic [Feb. 2020] and by June 2020 it had spread around the world. The D614G mutation stabilises the spike proteins that enable the virus to latch on to human cells and infect them…
The same mutations can arise by chance. But when variants around the world get a boost after acquiring several matching mutations (D614G, N501Y and E484K are all found in the South African and Brazilian variants, and in a subset of the Kent variant circulating in the south-west) it may mean convergent evolution is at work. This happens when virus in different parts of the world finds the same way to adapt to evolutionary pressure.

Of course, one wonders how creationists manage to rationalize viruses and bacteria at all, given that they aren’t in their bible and weren’t discovered until fairly recently (viruses in the early 20th century; bacteria were discovered in the mid-17th century, but were not identified as the source of disease until the mid-19th century). And it’s been known since the 1940s that both viruses and bacteria evolve. The evolution of resistance to antibiotics and antiviral medicines is proof of that. As Jerry Coyne notes in his book, Why Evolution is True,  “This is natural selection, pure and simple. Everyone knows about drug resistance, but it’s not often realized that this is about the best example we have of selection in action.”*

As noted on The Health Site (emphasis added):

Changes that give the virus an advantage can quickly become dominant. For example, one mutation, named D614G, was found in 80 per cent of COVID-19 viruses sequenced just four months after it was first detected. Now, viruses without the D614G mutation are only commonly seen in parts of Africa. Another mutation, N501Y, is found in the variant B.1.1.7. This mutation is believed to be the result of infection of an immunocompromised individual and may contribute to the virus being more contagious and deadly. The B.1.1.7 UK variant became the dominant variant within three months and is now responsible for over 90 per cent of infections there.

And from NC State University:

Natural selection acts as an evolutionary force to increase the frequency of strains with beneficial mutations and decrease the frequency of strains with deleterious mutations – whether we focus at the intrahost level, i.e. within each infected individual, or the community/host population level, i.e. a viral metapopulation of sorts – according to the [dis]advantage said mutations confer to the viral variants. 

And the NC State site also offers this example:

For argument’s sake, let’s say it takes 5,000 individual viruses to make you sick. If you’re talking to someone who has the virus the closer you are to them the more virus you’ll be exposed to, especially if you both aren’t wearing masks. When you both put on masks and you back away from each other beyond 6 ft, you’re doing that to reduce the number viruses you might be exposed to. Ideally to a level below how many it takes to establish an infection in you. So now instead of breathing in 5,000 viruses, you breathe in 500.
But if the virus randomly makes a small change in its spike protein so now it can bind to your lung cells more tightly, more efficiently, maybe that virus variant doesn’t need 5,000 viruses to make you sick. Maybe that one only needs 1,000 or even 500. So now that strain will spread more efficiently through the population because it can get around the selection pressure we imposed on it… 

The piece continues (emphasis added):

RNA viruses in many ways are the best example of Darwinian evolution. For most RNA viruses the enzyme they make that copies their genome (viral RNA polymerase) can’t proofread and edit the copies they make…  Each infected cell can produce 500-60,000 daughter viruses. That’s a lot of copying so there are bound to be a lot of mistakes. 

But there’s a caveat and a worrisome one:

RNA viruses typically make one mistake out of every 10,000 to 1,000,000 bases copied per infected cell. However, the one exception to this actually is the coronaviruses. It is the only type of RNA virus I know of that DOES have the ability to proofread. 

Still, the article notes the current vaccinations should be reasonably effective even against an evolving virus:

…some of the new strains we’re seeing this winter harbor antigenic escape mutations which allow the virus to escape antibodies generated against the vaccine. But fortunately, our antibodies target many different regions of the virus and it’s unlikely that any single mutation would allow for complete escape. And while there haven’t been comprehensive studies, it does appear that current vaccines offer a lot of protection against these new strains.

For those readers who think a one- or two-time vaccination will be sufficient and we’ll all be back to “normal” (as in what we were doing in 2019), the scientists suggest a different reality, in large part because of the ongoing evolution of the coronavirus:

If the vaccines confer medium-lasting immunity, it could become yet another seasonal coronavirus causing local and seasonal epidemics… By the time it’s safer to congregate again, it’ll be a couple of years at least that we won’t have seen most friends and family.

And while vaccinations will help and certainly give us confidence, we’re still a long way from that “normal” return. But maybe when we do get back it’ll be a party…

So for me, after I’ve gotten both shots, I’ll be comfortable getting on a plane and going back to normal, albeit maybe a little more guarded, for the first year or so. And unless I see evidence that we’re not keeping up with its mutations, I suspect, 3-5 years out I’ll be back to more or less normal.
But how “normal” will the future be? The one variable that’s the hardest to predict is what do the rest of the humans on the planet do? The history books always say the “Roaring 20s” were a response to WWI. But the 1918 pandemic killed more than WWI. I would not be surprised to see another “Roaring 20s” in response to this pandemic.

This is evolution at work. This is how the mechanism of natural selection operates. Darwin, even though he was unaware of bacteria and viruses, was right about the mechanics behind how life — even viruses, which may not actually be alive — evolves. What more proof does anyone need that evolution is true?

~~~~~

* Penguin Books, 2010. Highly recommended reading; a concise and coherent (and occasionally witty) explanation of evolution and natural selection. for any reasonably intelligent layperson to enjoy. You may also enjoy Richard Dawkins’ rather longer 2010 book about evolution The Greatest Show on Earth (Simon and Schuster, 2010) or his 2016 book, The Ancestor’s Tale (Weidenfeld & Nicholson, 2016)

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