互补测验（complementation test）（http://www.biox.cn/content/20050825/34870.htm）是遗传学的一个重要问题，初次接触这个概念，不易理解。我想到《管锥编》有“盲跛互助”故事，拿这个故事来比况互补测验情形，效果不错。

“智者《法华玄义》卷一上引《百论》：“若神无触，身不能到，如盲跛二人相假能到”；“智目行足”之语亦见卷二、卷四。希腊古诗屡咏一跛一盲，此负彼相，因难见巧，合缺成全（One man was maimed in his legs, while another has lost his eyesight. The blind man, taking the lame man on his shoulders, kept a straight course by listening to the other’s orders. It was bitter, all-daring necessity which taught them how, by dividing their imperfections between them, to make a perfect whole）。十八世纪法国诗人寓言中国瞽人与瘫痪人相约，秉孔子“人当互助”（Aidons-nous mutuellement）之遗训，“我以尔视，尔以我行”（Je marcherais pour vous, vous y verrez pour moi）”（钱锺书《管锥编》第二册）。