关于分子生物学的,这句话怎么翻译,急!
While missense mutations can, in principle, be reverted either by a true reversion event or by a second site event,two noteworthy reversion systems have been developed that are based on an absolutely invariant amino acid in either the Cyc1 or Trp5 protein.求翻译,关键是 event 在这里是什么意思?