染色体独立地存在于细胞内 ,稳定地传给子代细胞且具有寄生性的基因叫做质粒。具有代表性的质粒是存在于细菌中的环状双股 DNA,并能人工地制作质粒。如将带有病原微生物抗原蛋白基因的质粒注射到皮肤或肌肉内就能将其导入细胞 ,该细胞就能够合成微生物抗原 ,就可诱导机体产生对 Chromosomes exist independently in the cell, stably transmit the progeny cells and the parasitic gene is called the plasmid. Representative plasmids are circular double-stranded DNA present in bacteria and are capable of producing plasmids manually. If the plasmid with the antigenic protein of pathogenic microbe injected into the skin or muscle can be introduced into cells, the cells can synthesize microbial antigens, can induce the body to produce pairs of