关于分子生物学的,这句话怎么翻译,急!Whilemissensemutationscan,inprinciple,berevertedeitherbyatruereversioneventorbyasecondsiteevent,twonoteworthyreversionsystemshavebeendevelopedthatarebasedonanabsolutely

　　关于分子生物学的,这句话怎么翻译,急!

　　Whilemissensemutationscan,inprinciple,berevertedeitherbyatruereversioneventorbyasecondsiteevent,twonoteworthyreversionsystemshavebeendevelopedthatarebasedonanabsolutelyinvariantaminoacidineithertheCyc1orTrp5protein.求翻译,关键是event在这里是什么意思?