You're taking a normal gene and you're over expressing it or expressing it more abundantly than normal in one particular spot of the body to have an effect.

我们在讨论一个正常基因的过表达,也就是在体内某一点的表达量,大大超过正常水准从而产生疗效

耶鲁公开课 - 生物医学工程探索课程节选