26 ◆质粒 pSC101的获得 ●In 1972, Cohen constructed a new plasmid beginning with DNA isolated from E. coli. Cohen named the plasmid pSC101 (“SC" for Stanley Cohen).The new plasmid had three important features: (1) it had only a single recognition site where EcoRI would cut the molecule, thus identifying the spot where the plasmid would open; (2) it had a sequence of nucleotides called an origin of replication, which is needed to initiate DNA replication; such a sequence stimulates plasmids to multiply in a host organism; (3) it contained a gene for resistance to the antibiotic tetracycline; thus, bacteria having the plasmid could resist the effects of tetracycline, whereas bacteria lacking the plasmid would be killed by the tetracycline. Cohen在重组DNA技术中杰出贡献26 ◆质粒 pSC101的获得 ●In 1972, Cohen constructed a new plasmid beginning with DNA isolated from E. coli. Cohen named the plasmid pSC101 (“SC" for Stanley Cohen).The new plasmid had three important features: (1) it had only a single recognition site where EcoRI would cut the molecule, thus identifying the spot where the plasmid would open; (2) it had a sequence of nucleotides called an origin of replication, which is needed to initiate DNA replication; such a sequence stimulates plasmids to multiply in a host organism; (3) it contained a gene for resistance to the antibiotic tetracycline; thus, bacteria having the plasmid could resist the effects of tetracycline, whereas bacteria lacking the plasmid would be killed by the tetracycline. Cohen在重组DNA技术中杰出贡献