Transposable elements insert into safe havens

Some transposable elements are targeted to specific safe havens. (a) The yeast Ty3 retrotransposon inserts into the promoter region of transfer RNA genes. (b) The Drosophila R1 and R2 non-LTR-retrotransposons (LINEs) insert into the genes encoding ribosomal RNA that are found in long tandem arrays on the chromosome. Only the reverse transcriptase (RT) genes of R1 and R2 are noted.