Transposable elements (q.v.) first detected as the cause of spontaneous mutations in E. coli. The majority of IS elements studied so far range in size from 0.7 to 1.8 kilobase pairs. IS termini carry inverted repeats of about 10 to 40 base pairs, which are believed to serve as recognition sequences for a transposase (q.v.). The IS also contains a gene that encodes the transposase. The genome of the E. coli strain sequenced in 1997 contained 10 different insertion sequences, and most of these were present at multiple sites along the chromosome. See Chronology, 1969, Shapiro; 1997, Blattner et al.
Subjects: Genetics and Genomics.