I was thinking about this (and other) threads we had not too long ago:
And I got the impression that some of the Genetic Entropy proponents around here might be suspecting that Genetic Entropy constitutes a good explanation for India’s purported “plummeting COVID-19 cases”, or declines in the rates of deaths and hospitalizations reported in different countries all over the world.
Before going on, let’s remind ourselves that GE is the idea that there is relatively constant, and vast(the overwhelming majority) class of mutations with deleterious fitness effects so small they are effectively invisible to natural selection, and that these will pretty much always predominate on net effect such that, through mutation accumulation the mean fitness of all carriers in the population will inevitably slowly decline, until mean reproductive rate drops below 1.0, in which case the population size will decline and the species eventually goes extinct.
Okay. Now let’s look at the Corona virus. The most genetically divergent strains are something on the order of about 50 mutations different from each other, and in the area of 15-30 mutations different from the first identified variants making the rounds back in december 2019 or thereabouts. A few tens of mutations in total are separating the different strains.
That means, if you think Genetic entropy is causing the declining Covid-19 cases and hospitalizations, that a Coronavirus carrying approximately 30-50 mutations of effectively invisibly small fitness effects, is decreasing it’s fitness from whatever it’s ancestral value was back in end 2019, to values below 1.0.
Now obviously that does not make sense. How can ~50 mutations of invisibly small fitness effects (s ≈ -0.00001 or less?) add up to a fitness decline so significant that the virus is supposedly going extinct?
It seems to me the most obvious explanation is that more widespread implementation of precautionary measures is what is taking effect. There’s just no sense saying the virus is somehow succumbing to a fitness decline due to mutation accumulation, when (first of all), the variants now known to dominate in most places are radically more infectious than when the pandemic began, and when we’re only dealing with such a small number of total mutations. It simply doesn’t add up to think of this as the result of GE.