RNA viruses may well be the ultimate r-selected species. The life cycle of an RNA virus includes a few steps. Infecting the cell, coopting the machinery of the cell, making copies of its self, assemble those copies into viral particles. Then the offspring need to escaping the cell, avoid the immune system, and find a new cell to infect. If it’s that simple then it’s seven steps.
I very much doubt it’s that simple. In fact the illustration above shows just the bit where the virus enters the cell and off it’s coat. There is an antiviral drug that works by frustrating it’s attempt shed it’s coat. Obviously it get’s even more complex yet again if we add in how the virus moves between host animals.
But the copy step is notable. In quantity and quality.
a typical RNA viral genome of 10,000 bases, a mutation frequency of 1 in 10,000 corresponds to an average of 1 mutation in every replicated genome. If a single cell infected with poliovirus produces 10,000 new virus particles, this error rate means that in theory, about 10,000 new viral mutants have been produced.
The quantity is high, but the quality is low. Amazingly there is method in this madness. The combination of high errors and high numbers creates something useful, a search scheme.
If you want to frustrate a virus then you need to shutdown, or a least narrow, the pathway through which one of the steps in the reproductive cycle. For example, improved hygiene and increasing social distancing works by making the movement between host animals harder. Anti-viral drugs target individual steps in the cycle. The immune system learns to recognize the virus and pick it off as it moves between cells. In all these case the challenge for the virus is to route around the resulting bottleneck.
Since most of it’s offspring are mutants, most of it’s offspring are sacrificed to searching for these alternate pathways. Like most r-selected reproductive strategies the vast majority of the offspring fail in the process. When the spider has a thousand babies it works out because takes that many to searches opportune door into the next cycle of reproduction. When the maple tree throws off billions of seeds during it’s life that works because it needs to run that many searches to find one that let’s it pass it’s genes into the next generation.
It must be vary frustrating for the inventor of an anti-viral. The stupid viruses can mindlessly find a route around his clever invention. Adamantine was approved for use in 1966, by the 2005-2006 US flu widespread flu strains had routed around the hole it plugged. I think we can assume that the route around was found quickly and what took most of the time was propogating it around the larger community of flu viruses.
There are interesting analogies to be drawn between this and the way we use r-selected designs in open source, platform, social-network, strategies. I need to stew on that.
As with most things these days, I draw analogies twix this and my job search. I keep trying to have the options be numerous and to try to treat the failed attempts casually. But my species is not naturally given to r-selected tactics.
“making copies of itâ€™s self” -‘