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