2021考研英語長難句復(fù)習(xí)（二十五）

　　

　　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 is passed down only from mothers.

　　【長難句分析圖解】

　　篇章超精讀

　?、貰ut some observers are skeptical, "There is a kind of false precision being hawked by people claiming they are doing ancestry testing," says Trey Duster, a New York University sociologist.

　　②He notes that each individual has many ancestors-numbering in the hundreds just a few centuries back.

　?、踄et most ancestry testing only considers a single lineage, either the Y chromosome inherited through men in a father's line or mitochondrial DNA, which is passed down only from mothers.

　　④This 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.

　　參考譯文

　?、俚怯行┯^察者對此表示懷疑。Troy Duster 是紐約大學(xué)的一位社會學(xué)家，他認(rèn)為“那些聲稱他們在進(jìn)行先祖測試的人其實在吹噓一種虛假的準(zhǔn)確率”。

　?、谒赋觯粋€人有著很多的祖先——往回追溯幾百年，祖先數(shù)量就以百計。

　?、廴欢蠖鄶?shù)的祖先測試都只考慮一個單一的族系，要么是從父親身上得來的男性攜帶的 Y 染色體，要么就是僅從母親身上遺傳的線粒體 DNA。

　　④這種 DNA 只能揭示 1~2 位祖先信息，而僅 3 代以前，一個人就有六位曾祖，而四代以前就有另外 14 位高祖。