It's a gene that's on the plasmid, and this particular gene confers a specific biological property to cells that have the plasmid and can use it properly.

它是质粒自带的基因,如果细胞能够获得这种质粒,并正确的利用它的话,这段基因就能赋予该细胞某种生物学特性

耶鲁公开课 - 生物医学工程探索课程节选

Yeast cells were grown in large numbers with this plasmid inside, they expressed the plasmid and so you made Hepatitis B surface antigen not in people but in cell culture where it was not normally formed.

体内携带这种质粒的酵母细胞大量增殖,它们表达质粒,因此,乙型肝炎表面抗原不是在人体内,而是在细胞培养环境下,以非正常方式形成的

耶鲁公开课 - 生物医学工程探索课程节选

One of the ways that it's used is to take the fertilized egg from an animal, a mouse, usually it's a mouse and inject in a vector that contains a gene that is involved in human disease of some sort.

其中一种应用就是,从动物,一般是老鼠体内取出受精卵,注入某种质粒,这种质粒带有与某些人类疾病相关的基因

耶鲁公开课 - 生物医学工程探索课程节选