Over evolutionary history, this ability of transposons to copy themselves to new locations has helped them to dramatically expand their representation in the mammalian genome.
“Transposons occupy as much as half of our entire genome, and they can be dangerous,?Nishikura says. “As a result, mechanisms have arisen through evolution to suppress their activity. This is particularly true in the egg and sperm, where maintenance of the genome’s integrity is critical.?
One of these suppression mechanisms involves short interfering RNA, or siRNA, a form of non-coding RNA that specifically targets and inactivates the stretch of DNA from which it originated. In the case of transposons, this would effectively limit their ability to act, thus protecting the genome from potential disruption.
Source:The Wistar Institute