Evolution of the IS CR3 Group of IS CR Elements

Abstract
The IS CR elements IS CR3 , IS CR4 , IS CR5 , IS CR14 , and IS CR16 all share a percent G+C of 68 to 69%. They also share between 75% and 97% identity in their transposase open reading frames. Furthermore, with the exception of IS CR5 , they are all found adjacent to sections of groEL that display the highest identity to the same gene from Xanthomonas spp. The combined information is consistent with the descent from an ancestral IS CR element in a Xanthomonas -like organism.