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Unpacking the Genome
解構基因組
As a Nigerian-born scientist specializing in genetics and health disparities, Rotimi foresaw the consequences of omitting Africans from genome studies years before many other researchers even noticed.
作為一名尼日利亞裔專門研究基因和健康差異的科學家，羅蒂米早在許多其他研究人員之前就預見到了將非洲人排除在基因組研究之外的后果。
And he was uniquely positioned to do something about it.
他處在一個獨特的位置，可以為此做些什么。
Born in Benin, Nigeria's fourth-largest city, Rotimi first saw health inequalities in a big way in America.
羅蒂米出生在尼日利亞第四大城市貝寧，他第一次在美國看到了醫療的不平等。
He came to the U.S. for graduate school at the University of Mississippi, where many of the state's wealthiest families send their children, a trip that introduced him to his first Big Mac.
他來到美國密西西比大學讀研究生，在那里，該州許多最富有的家庭都會把孩子送到那里，這趟旅行讓他第一次接觸到了巨無霸漢堡。
"I just couldn't eat it," he recalls.
“我就是吃不下”，他回憶道。
"I couldn't fathom the concept of bread, meat and leaves together."
“我無法理解面包、肉和菜葉混在一起的概念?！?/div>
Worse was the taste of inequality he got while traveling around the state.
最糟糕的是羅蒂米在密西西比州旅行時所感受到的不平等。
"That is when poverty speaks very loud, when you are in an environment with a lot of resources, but you don't seem to have them," he says.
“當你處在一個資源豐富的環境中，但你似乎一無所有，貧窮就會格外扎心，”他說。
He returned to Nigeria armed with a graduate degree.
他帶著研究生學位回到了尼日利亞。
But after six months of job searching, he had yet to find an opportunity to do the research he knew was needed.
但經過6個月的求職，還沒有找到機會做需要做的研究。
He returned to the U.S., eventually earning doctorate degrees in public health and epidemiology.
他回到了美國，最終獲得了公共衛生和流行病學的博士學位。
Those years deepened his awareness of the importance of genes to health.
讀博的那些年加深了他對基因影響健康的認識。
Life in Nigeria had already shown him that sickle cell disease was fated by birth, not by upbringing.
尼日利亞的生活已經告訴他，鐮狀細胞病是先天的，而不是后天發生。
Now, his research on hypertension among Africans around the world showed him that although lifestyle and the environment shape health, so does DNA.
現在，他對世界各地非洲人高血壓的研究表明，盡管生活方式和環境塑造了健康，但DNA也不可忽視。
As Rotimi was appreciating the power of genetic inheritance, scientists were on their way to sequencing the first human genome.
當羅蒂米正沉醉于基因遺傳的力量時，科學家們正在對第一個人類基因組進行測序。
Tightly coiled inside the nucleus of every human cell, the genome consists of about 20,000 genes that encode proteins guiding the multitude of biological processes happening all the time in our bodies.
基因組緊緊盤繞在每個人類細胞的細胞核內，由大約2萬個基因組成，這些基因編碼蛋白質，指導著我們身體中每時每刻都在發生的眾多生物過程。
Genes, in turn, are made of DNA, helical strands of compounds called nucleotides that contain chemicals called bases.
反過來，基因是由DNA，即核苷酸的螺旋鏈組成，核苷酸含有一種叫做堿基的化學物質。
These four different bases—known most commonly by the initials A, C, T and G—are the language of the genetic code that makes up each unique individual’s blueprint.
這四個不同的堿基——最常見的形式是首字母A、C、T和G——是構成每個個體藍圖的遺傳密碼的語言。
A human genome—that is, the complete set of a person’s genes—consists of 3 billion bases.
一個人的基因組，也就是一個人的基因的完整集合，由30億個堿基組成。
The Human Genome Project, which was completed in 2003—by then, Rotimi was teaching microbiology at Howard University, in Washington, D.C.—sequenced most of a single person's genome.
人類基因組計劃于2003年完成，當時羅蒂米正在華盛頓特區的霍華德大學教微生物學——對一個人的大部分基因組進行測序。
The breakthrough wasn't so much the sequence itself but the technology.
這一突破與其說是序列本身，不如說是技術。
If research could match diseases or drug reactions to errant genes, doctors could tailor treatments around the unique genome of each patient.
如果研究能夠將疾病或藥物反應與出問題的基因相匹配，醫生就可以針對每個病人的獨特基因組量身定做治療方案。
To arrive there, though, scientists had to study the small ways a genome varies from one person to the next.
但要實現這樣的治療，科學家們就不得不研究不同人的基因組的細微差異。
The tiny fraction of our DNA that differs, researchers thought, had to be responsible for many inherited conditions.
研究人員認為，我們DNA中微小的差異，必然影響著許多遺傳疾病。
What they needed to study was not one genome but many.
他們需要研究的不是一個基因組，而是多個基因組。
They were looking for changes to single bases—a mutation from an A to a C, or a G to a T—among the 3 billion in a human genome.
他們正在人類30億基因組中尋找單個堿基的變化——從A到C的突變，或者從G到T的突變。
These can occur when DNA replicates, either when a baby is conceived or as cells divide during our lives.
這些可能發生在DNA復制的時候，或者是懷孕的時候，或者是在我們的生命中細胞分裂的時候。
These swaps, called single nucleotide polymorphisms (SNPs, pronounced snips), are often harmless but sometimes alter how a gene works, raising the risk for certain diseases.
這些突變稱為單核苷酸多態性（簡稱SNP），通常無害，但有時會改變基因的工作方式，增加某些疾病的風險。
The wrong SNPs can render people more susceptible to Alzheimer’s, some blood diseases, male infertility and cancer, among other conditions.
錯誤的SNP會使人更容易患上阿爾茨海默氏癥、一些血液疾病、男性不育癥和癌癥等疾病。
And once they're in the genome, they can be passed to the next generation.
一旦錯誤的SNP進入基因組，就會傳給下一代。
Precision medicine is based on the idea that finding a culprit SNP can lead to treatments targeted against the gene in which that SNP sits.
精準醫學是基于這樣一種想法：找到罪魁禍首SNP，就可以針對SNP所在的基因進行治療。
To find SNPs, researchers conduct association studies in which they compare whole genomes of many people.
為了發現SNP，研究人員進行了相關研究，比較了許多人的整個基因組。
After the Human Genome Project was done and the cost of sequencing genomes came down, these genome-wide association studies picked up the pace.
人類基因組計劃完成后，測序基因組的成本降低了，這些全基因組關聯研究加快了步伐。
But they suffered from a diversity problem: Almost none of them included African genomes.
但研究面臨著一個多樣性問題：幾乎沒有一個包括非洲基因組。
When those first few people left Africa 100,000 years ago, they took their inherited SNPs along with them.
10萬年前，第一批人離開非洲時，他們帶走了遺傳的SNP。
But they left behind an enormous amount.
但是還留下了許多。
And the larger population that remained in Africa meant more genomes churning out variety, generation upon generation.
而留在非洲的更多的人口意味著更多的基因組，一代又一代地生產出各種各樣的基因。
Because the ancestral trees of Africans have been branching out for so much longer than those of Europeans and Americans, they contain much more variation.
由于非洲人的祖先樹比歐洲人和美國人的分支要長得多，所有產生了更多的變異。
In fact, African genomes are the most diverse of any on the planet.
事實上，非洲的基因組是地球上最多樣化的。
"We compared European and Asian populations to each other," says Sarah Tishkoff, a geneticist at the University of Pennsylvania,
“我們對比了歐洲和亞洲的人口，” 賓夕法尼亞大學的遺傳學家莎拉·蒂什科夫說，
"and they were more similar than any two African populations we looked at."
“他們比我們觀察的任何兩個非洲人都更相似?！?/div>
When it comes to genetic diversity, Africa has a 100,000-year head start.
在基因多樣性方面，非洲領先10萬年。
譯文由可可原創，僅供學習交流使用，未經許可請勿轉載。
| 重點單詞 | 查看全部解釋 | |||
| certain | ['sə:tn] |
想一想再看 adj. 確定的，必然的，特定的 |
||
| opportunity | [.ɔpə'tju:niti] |
想一想再看 n. 機會，時機 |
||
| diverse | [dai'və:s] |
想一想再看 adj. 不同的，多種多樣的 |
聯想記憶 | |
| errant | ['erənt] |
想一想再看 adj. 錯誤的，脫離正途的，漫游的 |
聯想記憶 | |
| enormous | [i'nɔ:məs] |
想一想再看 adj. 巨大的，龐大的 |
聯想記憶 | |
| geneticist | [dʒi'netisist] |
想一想再看 n. 遺傳學者 |
||
| sickle | ['sikl] |
想一想再看 n. 鐮刀 |
||
| alter | ['ɔ:ltə] |
想一想再看 v. 改變，更改，閹割，切除 |
聯想記憶 | |
| precision | [pri'siʒən] |
想一想再看 n. 精確，精密度 |
||
| variation | [.vɛəri'eiʃən] |
想一想再看 n. 變化，變動，變種，變奏曲 |
