A10-kb dna fragment digested with restriction endonuclease ecori yielded fragments 4kb and 6kb in size. when digested with bamhi, fragments 1, 3.5, and 5.5 were generated. concomitant digestion with both ecori and bamhi yielded fragments .5, 1,3, and 5.5 kb in size. give a possible restriction map for the original fragment.