Complex sentence: A similar analysis of E. coli and S. enterica strains revealed that they evolved much slower than S. thermophilus where strains that had diverged 250 thousand years ago still contained the same spacer complement.
Split into simpler sentences: A similar analysis of "E. coli" and "S. enterica" strains revealed that they evolved much slower than "S. thermophilus". The latter's strains that had diverged 250 thousand years ago still contained the same spacer complement.