Figure 2.

Retrotransposition of mammalian SINE insertions. (A) The master SINE copy is transcribed by RNA polymerase III. (B) LINE-derived enzyme nicks a chromosome strand at the motif AATTTT. (C) The poly-A tail of a transcribed SINE binds to the free TTTT and acts as a primer for LINE-derived reverse transcriptase. A nick on the opposite strand frees the complementary target site duplication sequence. (D) Reverse transcriptase synthesizes complementary strands. (E) A new SINE insertion with characteristic target site duplications. Adapted from (Cordaux and Batzer 2009). (This figure appears in color in the online version of Journal of Heredity.)