DNA Tests Can’t Tell You Your RaceDNA检测无法验明种族

杰克·赫雷拉

Its always a mess when Latinx1 folks take DNA tests. Things go alright， until we get to the “ancestry2” portion， which some commercial genetic tests label as “ethnicity.”

拉美裔做DNA检测总是一片混乱。本来一切正常，可一旦涉及“血统”部分（一些商业性基因检测称之为“种族渊源”）就会乱套。

My grandfather is Mexican， but fair3-haired and blue-eyed （we sometimes call people who look like him bolillo， which means “white bread”）. When he got his report back from Family-TreeDNA， he found out he had more North American ancestry than expected. My friends brother， also Mexican， came into the living room with his tests results printed out. “I found Im 3 percent black，” he said.

我祖父是墨西哥人，但金发碧眼（我们有时称他这类长相的人为bolillo，意为“白面包”）。他收到家庭树基因检测公司的检测报告后，发现自己的北美血统成分高于预期。我朋友的兄弟也是墨西哥人，他拿着打印的检测结果走进客厅说：“我发现自己有3%的黑人血统。”

In the past few years at-home genetic testing has grown into a billion-dollar industry; since 2013， more than 26 million people have sent in their DNA for analysis. And while companies like 23&Me， AncestryDNA， and MyHeritage claim to be able to tell your “ethnicity”—a word they know many people will read as a synonym for “race”—none of them explicitly offer to tell consumers their racial make-up. Theres one simple reason for that： The science just doesnt exist.

在過去几年里，居家基因检测已发展成为一个规模达10亿美元的产业；自2013年以来，已有2600多万人将自己的DNA送去检测。虽然诸如我与23对染色体公司、家谱基因检测公司和MyHeritage之类的公司声称能验明人的“种族渊源”——他们知道很多人会把这个词解读为“种族”的同义词——但它们当中没有任何一家公司明确表示可告知消费者其种族成分。原因很简单：这种科学知识根本不存在。

To understand this， lets go back to my friends brother. He thought the test told him he was “3 percent black，” when in fact it reported that he had a 3 percent chance of having genetic ancestry from some part of the African continent.

为了理解这一点，我们再回到刚才我朋友的兄弟的例子。他以为检测结果显示他有“3%的黑人血统”，但其实检测报告说的是他的祖先来自非洲大陆某地的概率是3%。

Hows that different than being “3 percent black”？ First off， that percentage is being interpreted incorrectly. A lot of people read their DNA tests like a pie chart： Youre 25 percent this or 50 percent that. But thats not at all what the statistics represent.

这与“3%的黑人血统”有何不同？首先，对该百分比的解读有误。很多人将自己的DNA检测结果解读为一张饼图：你有25%的这个或50%的那个。但那根本不是该统计数据所表示的意义。

“They are fractions， estimates. Its saying that your genome has a certain percent estimate of representing a certain area，” says Marcus Feldman， a professor of biological sciences at Stanford University and director of the Morrison Institute for Population and Resource Studies.

“它们是分数，是估值，表示你的基因组按估算有一定比率代表某个地区。”斯坦福大学生物学教授、莫里森人口与资源研究所所长马库斯·费尔德曼说。

Feldman explains that when it comes to peoples roots， the tests are saying something more like： Were 30 percent confident that your DNA indicates ancestry from Okinawa， Japan. Thats not the same thing as saying someone is 30 percent Okinawan.

費尔德曼解释说，就寻根问祖而言，此类检测结果更像是在说：我们有30%的把握相信，你的DNA表明你的祖先来自日本冲绳。这不等于说某人有30%的冲绳血统。

The vast majority of human DNA—were talking 99.9 percent—is entirely identical between individuals. So when the code diverges between two people， thats interesting to scientists. A DNA ancestry test scans the entirety of your genome looking for single-letter differences. Statistical experts like Feldman have figured out that people from the same continent， on average， tend to have certain variations in the same regions of DNA. Still， its impossible to say that one tiny nuance comes from a specific place; analysts can only note when someones differences overlap a lot with a general geographic group.

绝大多数的人类DNA——我们说的是99.9%——在个体之间是完全相同的。因此，当两人之间的DNA密码有差异时，就会引起科研人员的关注。DNA血统检测筛查你的整个基因组，搜寻单字母差异。费尔德曼等统计专家发现，一般来说，来自同一大洲的人往往在相同的DNA区域有特定变异。但尚无法断言某一细微变异来自具体哪个地方；只有当某人的变异与某一地域整个群体有很多共同之处时，分析人员才会关注。

“You cant take your DNA and chop it up and say， ‘This bit came from here， and that bit came from there，” Feldman says， laughing.

费尔德曼笑言：“你不能把自己的DNA剁碎，然后说‘这一小块来自这里，那一小块来自那里。”

You might think your ancestry works sort of like inheriting genes from your parents—an even 50/50 split. But thats not the case when you go back another generation， as DNA reshuffles4 and reorganizes with every new transfer. So even if your mom gave you 50 percent of her own genes， doesnt mean you got an even portion of， say， her Pakistani parents. In fact， if you dig far enough， its possible youll find a direct ancestor that you have no genes in common with.

你或许认为自己的血统有点像继承父母的基因，是对半开。但再上溯一代则不然。因为每次新的传承都会发生DNA重排、重组。因此，即使你妈妈将她50%的自身基因传给你，也不意味着你等比均分到（比如说）她的巴基斯坦父亲或母亲的基因。事实上，如果挖掘得足够深远，你可能会查找到一个与你之间毫无共同基因的直系祖先。

This means that you and your sibling can have significantly different ancestry results， given youve each inherited different portions of your parents DNA （unless youre identical twins）.

这意味着你与兄弟姐妹之间在血统检测结果上可能会有明显差异，因为你们各自继承了不同比例的父母DNA（除非你们是同卵双胞胎）。

That brings us to another important detail： the fact that ancestry and physical appearance （or phenotypic5 traits） dont directly overlap. Characteristics like skin color， hair texture， and eye shape are controlled by thousands of different genes—separate from the ones scientists look at when composing an ancestry profile. As a result， someone with a high estimate of West African ancestry might not look or even identify as black. Similarly， an individual whose tests come back with a very low estimate of West African ancestry might actually be black.

由此我们又要说到另一重要细节：事实上，血统与外表（或称表型特征）并不直接相对应。肤色、发质和眼形等特征受数以千计的不同基因控制，与科研人员编制血统图谱时审视的基因无关。因此，一个据估算有很高比率是西非血统的人可能长相不像黑人，甚至鉴别不出来是黑人。同样，某人的检测结果估算出具有西非血统的比率非常低，却可能确实是黑人。

Thats why geneticists havent devised a test that can conclusively determine a persons race. And in a way， its impossible. Race is about how we identify and are identified; its more than a question of appearance—its a question of culture， history， geography， and family. It cant be boiled down to6 genetics and percentages.

这就是为什么遗传学家尚未发明能确凿判定一个人所属种族的检测方法。从某种程度上说，毫无可能。种族事关我们如何认同自我身份以及他人如何认知我们的身份；这不只是外表问题，更是文化、历史、地理和家族问题。它不能简单归结为基因信息和百分比。

“Its fundamentally flawed to think that a genetic test can figure out race，” says Sarah Tishkoff， a professor of genetics and biology at the University of Pennsylvania. “Race is a socially constructed concept. How someone self-identifies in terms of their ethnicity or race may be different than what their genetic ancestry tells us.”

宾夕法尼亚大学遗传与生物学教授萨拉·蒂什科夫说：“认为基因检测可验明种族是个根本性错误。种族是社会建构概念。个人如何认同自己的种族渊源或种族，与其遗传血统透露的信息可能有所不同。”

European colonizers invented the concept of race 500 years before the double helix was discovered. Many of their terms for describing human difference， based on traits like skin color and facial features， are still used in our censuses and societies today. “I think in that period when Europe was dominant， [racial terms] were a way of classifying levels of inferiority，” Feldman says， speaking of the birth of white supremacy. “It was a validation of colonialism.”

早在人类发现双螺旋结构的500年前，欧洲殖民者就创立了种族这一概念。他们根据肤色和面容等特征描述人类差异的许多词语在现今的人口普查和社会中仍在使用。“我认为，在欧洲占主导地位的那个时期，［种族词语］是一种划分低劣等级的方式，意在证实殖民主义的合理性。”费尔德曼在谈及白人至上主义的问世时说道。

In an ironic twist， however， race—and racism—have affected how we understand ancestry. DNA tests like 23andMe pack a strong Eurocentric bias because theyre based on genetic research thats largely from one continent. In fact， the original samples analyzed by the Human Genome Diversity Project didnt include any samples from North America.

然而，具有讽刺意味的一个变化是，种族和种族主义已经影响到我们对血统的理解。我与23对染色體等公司的DNA检测带有强烈的欧洲中心主义偏见，因为它们所依据的基因研究结果大多来自一个大洲。事实上，人类基因组多样性项目所分析的原始样本不包括任何来自北美的样本。

My grandpas tests， for instance， included incredible granular detail on his profile from the Iberian peninsula （it went so far as to suss Sephardic Jews from other Spaniards）. But his American ancestry just said “North America” （a category that lumps7 Inuits together with Aztecs8）.

例如，我爷爷的检测结果上，他源自伊比利亚半岛的基因图谱相关细节精微到不可思议的地步（甚至验明他归属西班牙系犹太人，有别于其他西班牙人）。但对他的美洲血统只说是“北美”（一个将因纽特人与阿兹特克人混为一谈的类别）。

All this leaves us with the question of how we should talk about race as genetic analysis becomes more commercialized and common. The results， no matter how personal， can have serious social ramifications. There are websites that offer advice to white people on using DNA testing to apply for “minority status” in college admission. That cyn-ical use of biological data should make us deeply uncomfortable—and it should make us think further about the information that helps us define our own identities.

这一切留给我们的问题是，随着基因分析更趋商业化和更为普遍，我们应如何看待种族问题。检测结果虽然是私事，但会产生严重的社会影响。有些网站建议白人利用DNA检测结果来以“少数族裔身份”报读大学。这种对生物学数据的自私利用应让我们深感不安，促使我们深思那些有助于我们界定自我身份的信息。

The history you glean9 from a DNA test comes from context that biology cant provide. Its your choice to seek out that context， draw the lines to ancestors and colonial legacies， and determine who you are today.

你從DNA检测结果中获悉的历史来自于生物学无法提供的背景。就看你要不要去探明这一背景，找出它与祖先和殖民遗毒的联系，确定今天的你是谁。

（译者为“《英语世界》杯”翻译大赛获奖者）

1 Latinx（尤指住在美国的）拉美裔人。  2 ancestry世系，血统。  3 fair（头发）浅黄的，金色的。

4 reshuffle重新安排，改组。

5 phenotypic表型的。  6 boil down to归结为。

7 lump把……归并在一起，混为一谈。  8 Aztec阿兹特克人（即墨西哥印第安人）。

9 glean费力地收集。