In a paper from Taekjip Ha at the University of Illinois, Urbana-Champaign, and Smita Patel at the University of Medicine and Dentistry of New Jersey that appears in the early online edition of Nature this week, their team found that during DNA replication, RNA primers "are made 'on the fly' during ongoing DNA synthesis and that the leading-strand T7 replisome does not pause during primer synthesis, contrary to previous reports." This accounts for the fact that the two replicating stra