ELi5: what causes genes to mutate?
In: Biology
The enzymes that make copies of DNA rarely make mistakes. But like 0.00001% (or something) of the time they insert the wrong base into the new DNA copy. Since genomes can be hundreds of millions of base pairs long, those mistakes happen all the time.
Even so, it’s really rare that the mutation actually affects a gene, since genes only make up about 2% of the total genome. And even if it does, it rarely has any affect on the product of the gene. But once in a really really long while, a beneficial mutation to a gene gives the organism some kind of advantage compared to other organisms.
Mutagens are things (like sunlight or idk, nicotine?) that increase the number of mistakes made by DNA-copying enzymes. If mutations have any effect on the organism, it’s almost always a bad thing. Beneficial mutations are incredibly rare.
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