In Cell this week, investigators in France and the US show that "single-stranded DNA transposition is coupled to host replication." They describe a connection between the transposition of IS608 and ISDra2 — members of the same insertion sequence family — which they suggest "uses obligatory single-stranded DNA intermediates, and the host replication fork." Thus, the authors report, "replication direction through the IS plays a crucial role in excision," in that, replication activity