Selective Sweep in the Human Population
Last week, I wrote about the “it must get milder myth”. I’d like to expand on this a bit and explain how a concept called “selective sweep” affects the human response to lethal pathogens. We know that viruses evolve in response to changing conditions, such as previous infections in a host or widespread use of vaccines. The human species also responds to dangerous infections. We have individual immune responses to viruses. There are also changes at a population level. The genes that code for our immune system vary greatly from individual to individual. This partly explains why two people with similar apparent characteristics can have very different responses to the same infection. When a new virus rapidly expands in a naive population, it may kill many individuals. However, due to variation in human genetics, some individuals, through sheer chance, will have an immune system that prevents serious disease. These individuals will be the only ones who can give rise to the next generation of humans. Hence, in future generations, the new virus will appear to be “milder”, simply because all the people who were susceptible to it died and did not pass on their genes. This is what survival of the fittest means when applied to humans exposed to a new, lethal virus. There is substantial evidence that there have been large die-offs in humans in response to a new infectious disease that preserved a remnant population that later expanded its numbers after the die-off. The evidence for these die-offs lies within our genomes. There are signs of “selective sweep” in our genetic makeup, i. e., evidence that certain gene variants became common because they conferred a survival advantage to the initially small group of individuals who had them. Smallpox is one of the diseases that affected humans in this way. Smallpox was dangerous to Europeans but was far more lethal to Native Americans. The European population had been culled of susceptible individuals for many years by smallpox. Native Americans had never been exposed to the virus before. For this reason, smallpox killed 30% of infected Europeans but killed 90% of Native Americans. The virus obviously had not gotten milder despite having infected humans for thousands of years before it entered the Native American population. SARS-2 is thus far not nearly as lethal as smallpox. However, there is evidence that some of the new strains are getting more lethal. How lethal can SARS-2 get? We don’t know. The statement that the virus must get milder because it is in the virus’s self-interest is made by people with a weak understanding of biology. I’m afraid that this includes more than a few people in public health.
Name the Evil
I have been greatly disturbed by reports of attacks on Asian Americans. Not much information has been provided on why these attacks are happening. I think it is possible that the mass media coverage of what is occurring in China is one factor that is causing weak-minded individuals to behave in this way. Xi Jinping is the absolute dictator of a totalitarian State. But you wouldn’t know this by the way the media covers the evil that is occurring in China. When some new atrocity is revealed, terms like “China”, “the Chinese”, and “the Chinese government” are referenced. China is a country; the Chinese are a people; and the Chinese government is one man: Xi Jinping. “China” did not order the construction of concentration camps and the rape, torture, murder and genocide of the Uyghur people; Xi Jinping did. “China” didn’t order the destruction of freedom in Hong Kong; Xi Jinping did. “China” didn’t order the release of the SARS-2 on an unsuspecting world; Xi Jinping did. Why can’t the media name the source of evil in China? It is one man: Xi Jinping. It took a long time, too long, for people to understand that the ruler of Germany in the 1930s was an evil man. Personally evil. Given the power of modern weapons, we cannot afford to ignore the fact that Xi Jinping is a personally evil man. Not because he is a Communist. He has had real Marxists arrested and imprisoned. Xi Jinping is evil because there is something missing in his brain. The media should stop blaming “China” for the evil being orchestrated by one man.
Reference:
Natural selection and infectious disease in human populations.(2014) Karlsson et al. Nature Reviews Genetics.
https://www.nature.com/articles/nrg3734
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