My understanding is that transposon repression mechanisms (like piRNAs) are dramatically upregulated in the germ line. They are already very close to 100% effective in most cells under normal conditions, and even more so in the germ line, so that most children do not have any more transposons than their parents.
(More generally, my understanding is that germ line cells have special stuff going to make sure that the genome is passed on with minimal errors. Non-germ cells are less “paranoid” about mutations.)
Once the rate is low enough, it’s handled by natural selection, same as any other mutations.
My understanding is that transposon repression mechanisms (like piRNAs) are dramatically upregulated in the germ line. They are already very close to 100% effective in most cells under normal conditions, and even more so in the germ line, so that most children do not have any more transposons than their parents.
(More generally, my understanding is that germ line cells have special stuff going to make sure that the genome is passed on with minimal errors. Non-germ cells are less “paranoid” about mutations.)
Once the rate is low enough, it’s handled by natural selection, same as any other mutations.