Early thinking on the nature of mismatch repair

Replication error correction by mismatch repair relies on the strand-directed nature of the reaction. Ephrussi-Taylor and Gray attributed the marker-dependent recovery of pneumoccocal transformants to a mismatch-provoked repair reaction characterized by a strong strand bias and long excision tracts. This idea was extended by Wagner and Meselson in the context of a study on mismatch repair of multiply marked lambda heteroduplexes, with the explicit proposal that strand-directed mismatch repair could provide a mechanism for correcting DNA biosynthetic errors.