Abstract
The four restriction enzymes ApaI (5'-GGGCCC), EagI (5'-CGGCCG), NaeI (5'-GCCGGC), and SmaI (5'-CCCGGG) were found to produce distributions of DNA fragment sizes useful for mapping of the Haemophilus influenzae Rd genome by pulsed-field agarose gel electrophoresis. ApaI produced 21 fragments (range, 1.6 to 305 kilobases [kb]), EagI yielded 30 fragments (0.6 to 339 kb), NaeI produced 32 fragments (2.3 to 290 kb), and SmaI yielded 16 fragments (6.0 to 377 kb). Summation of the fragment lengths in each digest yielded estimates for the size of the H. influenzae chromosome ranging from 1,834 kb.