Then he read about research tracing the Y sex chromosome, which is passed intact from father to son, all the way back to the time of Aaron, the single progenitor of the priestly cohen caste 3,000 years ago.

• 接着他阅读了有关Y性染色体的研究材料。Y染色体完整地从父亲传递给儿子，这就可以一路追溯到圣人艾伦的年代。艾伦是3000年前的教士科恩种姓的惟一祖先。