And it's by looking at the pattern of genetic variation, the pattern of these markers in people all over the world, and assessing the relative ages when they occurred throughout our history, that we've been able to construct a family tree for everybody alive today.
通过观察基因变异的类型， 全世界人们携带的标签的类型， 来分析标签产生的年代， 正是我们用来给每个人创造家谱的方法。