No reasonable person reads “found genetic mutations in every astronaut” to plausibly mean “found bog standard genetic mutations everyone’s got.” This is pop science communication—journalism—not the actual scientific study. The goal isn’t scientific precision, it’s democratizing technical work
Really? I think everybody in the entire world knows somebody who's died from cancer, and the more educated of those people know that cancer is caused by genetic mutations. Also the theory of evolution is based on random genetic mutations - a very popular theory. I think a reasonable person would therefore know that everybody gets random genetic mutations over time.
To put it concretely, if the chance of a random gene mutation is 10^-4 to 10^-6 per gene per generation, and there are 37 trillion cells in a human body, each cell containing about 20k genes, (all numbers from quick google searches) then the odds of having NO genetic mutations occur in your body in one day would be (forgive my back of the envelope math, assuming a generation is 20 years): (1 - 10^-6)**(37 trillion * 20000 / 365 / 20). My calculator can't keep enough precision to make this nonzero. i.e., everyone has genetic mutations constantly which makes the title of the article completely uninformative.
There are some tricks to reduce the number of important mutations.
Germinal cells reproduce very slowly, so the eggs and sperm have fewer mutations.
Also, cells inside the guts have some cascade method. The cells near the wall reproduce very seldom, but the intermediate cells reproduce faster, and the inner cells reproduce even faster. The inner cells that are reproducing fast die or get washed away, so the big number of possible mutations is removed. And the slow reproducing cells near the wall create more cells to replace the intermediate cells that replace the inner cells.
