Abstract
Phage D10, a Vibrio cholerae O-1 El Tor group X phage, is one of the five newly isolated phages used in the phage typing scheme developed for V. cholerae O-1 biotype El Tor and belongs to the Myoviridae family. From electron microscopic studies it is shown that phage D10 has a DNA genome of 32 +/- 0.2 kb. This is the first report where it has been shown by the construction of a partial denaturation map that this vibriophage genome is nonpermuted and has cohesive ends. The location of the ends of the DNA in the phage head has also been inferred.