Nearly Half of Our Genome Is Composed of Transposon Repeats

Essay

Nearly half of our genome is composed of transposon repeats, some of which can actively transpose, occasionally causing disease by inserting into or close to genes, (causing gene inactivation or inappropriate expression of oncogenes). Many of them work by making copies that transpose and so can increase in copy number, and so there is a need to limit the number of actively transposing sequences in case they overwhelm the genome. Two types of small RNAs act to limit the spread of transposons. What are these RNAs and where do they work?