第五段
But some observers are skeptical, "There is a kind of false precision being hawked by people claiming they are doing ancestry testing," [strike]says[/strike]Trey Duster, a New York University sociologist. [strike]He notes[/strike] that each individual has many ancestors-numbering in the hundreds just a few centuries back. Yet most ancestry testing only considers a single lineage, either the Y chromosome inherited through men in a father's line or mitochondrial DNA, which a passed down only from mothers. This DNA can reveal genetic information about only one or two ancestors, even though, for example, just three generations back people also have six other great-grandparents or, four generations back, 14 other great-great-grandparents.
啊,这一段,又出现了,我们心爱的but,划下来!但是观察家有怀疑。
出矛盾了,就出激情了,出现在段首的转折,说明这一整段都是对前文的一个转折,有可能是一个颠覆,太激动了,赶紧看看吧!
仔细看看,这一段都是一个人说的话,那么这个人就是持有怀疑的观察家的一个代表,对不对?他说的话代表了大部分怀疑者的意见,所以作者引用他说的话。 他说了什么?做家谱测试的时候,达不到人们宣称的精确性。
又出现了一个yet ,又是一个小转折,说的什么?大部分的测试只考虑单一谱系,之后的内容又是说这个只考虑单一谱系的细节了,可以不看。yet有仍然,还是的意思,那么就是说yet后面这一部分说的是不好的,是Trey Duster这个人质疑的内容,对吧?
下一句DNA只能揭示一两个先祖的基因信息,后面看到for example 这个词,我们又解放了,后面不用看了。
那么这一段又被我们看完了,看出这一段的主题了吗? |