DNA Tests Can’t Tell You Your RaceDNA檢測無法驗明種族

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檢測總是一片混亂。本來一切正常，可一旦涉及“血統”部分（一些商業性基因檢測稱之為“種族淵源”）就會亂套。

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，但金發碧眼（我們有時稱他這類長相的人為bolillo，意為“白面包”）。他收到家庭樹基因檢測公司的檢測報告后，發現自己的北美血統成分高于預期。我朋友的兄弟也是墨西哥人，他拿著打印的檢測結果走進客廳說：“我發現自己有3%的黑人血統。”

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.

在過去幾年里，居家基因檢測已發展成為一個規模達10億美元的產業；自2013年以來，已有2600多萬人將自己的DNA送去檢測。雖然諸如我與23對染色體公司、家譜基因檢測公司和MyHeritage之類的公司聲稱能驗明人的“種族淵源”——他們知道很多人會把這個詞解讀為“種族”的同義詞——但它們當中沒有任何一家公司明確表示可告知消費者其種族成分。原因很簡單：這種科學知識根本不存在。

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.

為了理解這一點，我們再回到剛才我朋友的兄弟的例子。他以為檢測結果顯示他有“3%的黑人血統”，但其實檢測報告說的是他的祖先來自非洲大陸某地的概率是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.

這與“3%的黑人血統”有何不同？首先，對該百分比的解讀有誤。很多人將自己的DNA檢測結果解讀為一張餅圖：你有25%的這個或50%的那個。但那根本不是該統計數據所表示的意義。

“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.

“它們是分數，是估值，表示你的基因組按估算有一定比率代表某個地區。”斯坦福大學生物學教授、莫里森人口與資源研究所所長馬庫斯·費爾德曼說。

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.

費爾德曼解釋說，就尋根問祖而言，此類檢測結果更像是在說：我們有30%的把握相信，你的DNA表明你的祖先來自日本沖繩。這不等于說某人有30%的沖繩血統。

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.

絕大多數的人類DNA——我們說的是99.9%——在個體之間是完全相同的。因此，當兩人之間的DNA密碼有差異時，就會引起科研人員的關注。DNA血統檢測篩查你的整個基因組，搜尋單字母差異。費爾德曼等統計專家發現，一般來說，來自同一大洲的人往往在相同的DNA區域有特定變異。但尚無法斷言某一細微變異來自具體哪個地方；只有當某人的變異與某一地域整個群體有很多共同之處時，分析人員才會關注。

“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.

費爾德曼笑言：“你不能把自己的DNA剁碎，然后說‘這一小塊來自這里，那一小塊來自那里。”

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.

你或許認為自己的血統有點像繼承父母的基因，是對半開。但再上溯一代則不然。因為每次新的傳承都會發生DNA重排、重組。因此，即使你媽媽將她50%的自身基因傳給你，也不意味著你等比均分到（比如說）她的巴基斯坦父親或母親的基因。事實上，如果挖掘得足夠深遠，你可能會查找到一個與你之間毫無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）.

這意味著你與兄弟姐妹之間在血統檢測結果上可能會有明顯差異，因為你們各自繼承了不同比例的父母DNA（除非你們是同卵雙胞胎）。

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.

由此我們又要說到另一重要細節：事實上，血統與外表（或稱表型特征）并不直接相對應。膚色、發質和眼形等特征受數以千計的不同基因控制，與科研人員編制血統圖譜時審視的基因無關。因此，一個據估算有很高比率是西非血統的人可能長相不像黑人，甚至鑒別不出來是黑人。同樣，某人的檢測結果估算出具有西非血統的比率非常低，卻可能確實是黑人。

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.

這就是為什么遺傳學家尚未發明能確鑿判定一個人所屬種族的檢測方法。從某種程度上說，毫無可能。種族事關我們如何認同自我身份以及他人如何認知我們的身份；這不只是外表問題，更是文化、歷史、地理和家族問題。它不能簡單歸結為基因信息和百分比。

“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.”

賓夕法尼亞大學遺傳與生物學教授薩拉·蒂什科夫說：“認為基因檢測可驗明種族是個根本性錯誤。種族是社會建構概念。個人如何認同自己的種族淵源或種族，與其遺傳血統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.”

早在人類發現雙螺旋結構的500年前，歐洲殖民者就創立了種族這一概念。他們根據膚色和面容等特征描述人類差異的許多詞語在現今的人口普查和社會中仍在使用。“我認為，在歐洲占主導地位的那個時期，［種族詞語］是一種劃分低劣等級的方式，意在證實殖民主義的合理性。”費爾德曼在談及白人至上主義的問世時說道。

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，具有諷刺意味的一個變化是，種族和種族主義已經影響到我們對血統的理解。我與23對染色體等公司的DNA檢測帶有強烈的歐洲中心主義偏見，因為它們所依據的基因研究結果大多來自一個大洲。事實上，人類基因組多樣性項目所分析的原始樣本不包括任何來自北美的樣本。

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，我爺爺的檢測結果上，他源自伊比利亞半島的基因圖譜相關細節精微到不可思議的地步（甚至驗明他歸屬西班牙系猶太人，有別于其他西班牙人）。但對他的美洲血統只說是“北美”（一個將因紐特人與阿茲特克人混為一談的類別）。

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.

這一切留給我們的問題是，隨著基因分析更趨商業化和更為普遍，我們應如何看待種族問題。檢測結果雖然是私事，但會產生嚴重的社會影響。有些網站建議白人利用DNA檢測結果來以“少數族裔身份”報讀大學。這種對生物學數據的自私利用應讓我們深感不安，促使我們深思那些有助于我們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檢測結果中獲悉的歷史來自于生物學無法提供的背景。就看你要不要去探明這一背景，找出它與祖先和殖民遺毒的聯系，確定今天的你是誰。

（譯者為“《英語世界》杯”翻譯大賽獲獎者）

1 Latinx（尤指住在美國的）拉美裔人。? 2 ancestry世系，血統。? 3 fair（頭發）淺黃的，金色的。

4 reshuffle重新安排，改組。

5 phenotypic表型的。? 6 boil down to歸結為。

7 lump把……歸并在一起，混為一談。? 8 Aztec阿茲特克人（即墨西哥印第安人）。

9 glean費力地收集。