““But your genes can also be different from those of your parents just through random mutation, which is the imperfect copying from one strand of DNA to another. It can literally be a cosmic ray from outer space that knocks into one of your genes and changes it. Genes sometimes jump from one place on the DNA molecule to another. These are called transposon genes. It could be that your parent’s eggs or sperm (or a plant’s ova and pollen) got messed with a little by some chemical. It could be radiation from some radioactive elements in Earth’s crust that caused a mutation. Sometimes viruses get into the reproductive cells of an organism and modify its genes. Virus manipulation can also be exploited deliberately—to adjust the genes of corn plants so they are tolerant of aggressive weed killer, for example.””
