新闻周刊:非洲基因对癌症研究很重要(3)

The Perils¹ of Exclusion²

排除在外的风险

Including Africa in the search for problematic SNPs has several crucial advantages.

包括非洲在内，寻找有问题的单核苷酸多态性有几个关键的优势。

SNPs involved in diseases like cancer are usually rare, and a rare SNP found in the genome of someone with cancer could lead a researcher to link the two.

与癌症等疾病相关的SNP很罕见，在癌症患者的基因中发现罕见的SNP可让研究人员将这两者联系起来。

But what seems like an uncommon³ mutation⁴ among European genomes may turn out not to be when Africans are added to the mix, says Nicola Mulder, who analyzes⁵ genetic⁷ data at the University of Cape⁸ Town in South Africa.

但是，在欧洲基因中看似罕见的突变当加入非洲基因时，可能并不罕见了，南非开普敦大学分析基因数据的尼古拉·穆德如是说。

That mistake could waste years of effort and lots of money.

那个错误可能会浪费多年努力和大量金钱。

A group of scientists once presumed that five genetic variants¹⁰ caused a dangerous thickening of the heart, even going so far as to tell people with those variants that their DNA¹¹ put them at risk for cardiac troubles.

一组科学家曾假设五种基因变异造成危险的心脏增厚，甚至告诉那些有变异的人其DNA可能会导致他们有心脏问题风险。

But they were wrong.

但他们错了。

Those five variants were not rare at all and in fact completely harmless.

这五种变异一点都不罕见，且事实上是完全无害的。

If the scientists had included African populations in their work, they might have known.

如果科学家已经把非洲基因囊括进了其研究中，那么他们可能已经意识到了这个问题。

More important, compared with Europeans and Americans, Africans have much better genomes for research, again because of their ancestral age.

更重要的是，和欧洲人、美洲人相比，非洲人有更多可研究的基因，这又是因为他们的祖先处在更早的年代。

Over time, as a genetic material is handed down from one generation to the next, SNPs tend to gather in clusters, making them easier for researchers to find.

随着时间的推移，随着遗传物质从一代传到下一代，SNP倾向于聚集成簇，使得研究者更容易找到它们。

As a consequence, they are more apparent in older genomes—in other words, African ones.

因此，它们在更古老的基因组中更为明显——换句话说，是在非洲。

"That can be of use to all populations," says Tishkoff.

“这对所有人群都有用，”蒂什科夫说。

For example, this clustering phenomenon led geneticists to a gene⁶ associated with LDL cholesterol¹² (the bad kind) and another related to inflammation.

例如，这种聚类现象导致基因学家发现了一种与低密度脂蛋白胆固醇(一种有害的胆固醇)有关的基因，另一种与炎症有关。

African genomes have been rubbing up against environmental threats for far longer than any others, forcing the appearance of some surprising traits that may hold vital clues about disease.

非洲基因对抗环境威胁的时长要大于其他地方的基因，这就形成了某些可能意想不到的性状，可能是治疗某些疾病的重要线索。

A genetic mutation that enables us to survive one hazard may also shackle¹³ us with a less harmful new trait.

一种能使我们在恶劣环境下存活的基因变异，可能会带给我们有些小伤害的新性状。

Take sickle¹⁴ cell anemia¹⁵: The gene behind this condition also protects against malaria¹⁶.

以镰状细胞贫血为例：导致这种疾病的基因也能预防疟疾。

Another mutation makes people immune to the parasite¹⁷ behind African sleeping sickness but also increases their risk of kidney disease.

另一种变异让人们对导致非洲昏睡病的寄生虫免疫，但也增加了患肾病的危险。

It's not hard to imagine, Tishkoff notes, a mutation that enabled people to survive some menace but also left them predisposed to cancer.

蒂什科夫称，不难想象，人类因这种变异在某些威胁下生存下来，但也因此易患癌症。

Though the menace disappeared—say, in the move from East Africa to North America—the variant⁹ remained.

尽管这种威胁消失了，比如从东非到北美的迁移，但这种基因变异仍然存在。

These relic¹⁸ mutations could help explain how or why cancer evolved.

这种遗留下来的突变可能会帮助解释癌症是怎样或者说为什么演变的。

"Given the vast genetic variation that exists in African genomes," Rotimi says,

“鉴于非洲基因组存在巨大的基因变异，”罗蒂米说，

"it is likely that we can find genetic variants that are important to cancer that may not be discovered from other human populations."

“很可能我们可以找到对癌症很重要的基因变异，而这种变异可能不会在其他人群中被发现。”

And just as African genomes can help us recover our collective past, they can also save us from a perilous¹⁹ future.

正如非洲的基因组可以帮助我们找回我们共同的过去一样，也可以把我们从危险的未来中拯救出来。

Some genetic abnormalities influence how our bodies respond to medications, a field known as pharmacogenomics.

一些基因异常会影响我们的身体对药物的反应，这是一个被称为药物基因组学的领域。

One variant, for example, leaves people with HIV less tolerant to an anti-retroviral drug, a discovery that is changing treatment regimens across sub-Saharan Africa.

如，有种变异使艾滋病毒感染者对抗逆转录病毒药物的耐受性降低，这一发现正在改变整个撒哈拉以南非洲地区的治疗方案。

Another messes with the breast cancer drug tamoxifen.

另一种药物与乳腺癌药物他莫西芬有关。

The more diverse the genome, the higher the odds²⁰ of finding mutations that may shape the choice of medication.

基因组多样化越大，发现决定药物选择的基因变异的几率越大。

"Increasing genomic research in Africa is going to benefit not just people of African descent," Tishkoff says, "but all people."

“在非洲不断增加基因组研究将不仅造福于非洲后裔，” 蒂什科夫称，“而且对全人类有益。”

1 perils   

极大危险( peril的名词复数 )； 危险的事（或环境）

参考例句：

• The commander bade his men be undaunted in the face of perils. 指挥员命令他的战士要临危不惧。
• With how many more perils and disasters would he load himself? 他还要再冒多少风险和遭受多少灾难？

2 exclusion   

n.拒绝，排除，排斥，远足，远途旅行

参考例句：

• Don't revise a few topics to the exclusion of all others.不要修改少数论题以致排除所有其他的。
• He plays golf to the exclusion of all other sports.他专打高尔夫球，其他运动一概不参加。

3 uncommon   

adj.罕见的，非凡的，不平常的

参考例句：

• Such attitudes were not at all uncommon thirty years ago.这些看法在30年前很常见。
• Phil has uncommon intelligence.菲尔智力超群。

4 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

5 analyzes   

v.分析( analyze的第三人称单数 )；分解；解释；对…进行心理分析

参考例句：

• This approach analyzes management by studying experience usually through cases. 这个学派通常从实例获得经验，用以分析管理。 来自辞典例句
• The econometrician analyzes statistical data. 经济计量学者要分析统计材料。 来自辞典例句

6 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

7 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

8 cape   

n.海角，岬；披肩，短披风

参考例句：

• I long for a trip to the Cape of Good Hope.我渴望到好望角去旅行。
• She was wearing a cape over her dress.她在外套上披着一件披肩。

9 variant   

adj.不同的，变异的；n.变体，异体

参考例句：

• We give professional suggestions according to variant tanning stages for each customer.我们针对每位顾客不同的日晒阶段，提供强度适合的晒黑建议。
• In a variant of this approach,the tests are data- driven.这个方法的一个变种，是数据驱动的测试。

10 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

11 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

12 cholesterol   

n.（U）胆固醇

参考例句：

• There is cholesterol in the cell of body.人体细胞里有胆固醇。
• They are determining the serum-protein and cholesterol levels.他们正在测定血清蛋白和胆固醇的浓度。

13 shackle   

n.桎梏，束缚物；v.加桎梏，加枷锁，束缚

参考例句：

• He's too young to shackle himself with the responsibilities of a family.他还太年轻，不能用家庭责任来束缚自己。
• This issue always is a shackle which confines the brand building of industry product.这个问题一直是限制工业品品牌塑造的桎梏。

14 sickle   

n.镰刀

参考例句：

• The gardener was swishing off the tops of weeds with a sickle.园丁正在用镰刀嗖嗖地割掉杂草的顶端。
• There is a picture of the sickle on the flag. 旗帜上有镰刀的图案。

15 anemia   

n.贫血，贫血症

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。
• I was put on iron tablets for my anemia.我曾因贫血吃补铁药片。

16 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

17 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

18 relic   

n.神圣的遗物，遗迹，纪念物

参考例句：

• This stone axe is a relic of ancient times.这石斧是古代的遗物。
• He found himself thinking of the man as a relic from the past.他把这个男人看成是过去时代的人物。

19 perilous   

adj.危险的，冒险的

参考例句：

• The journey through the jungle was perilous.穿过丛林的旅行充满了危险。
• We have been carried in safety through a perilous crisis.历经一连串危机，我们如今已安然无恙。

20 odds   

n.让步，机率，可能性，比率；胜败优劣之别

参考例句：

• The odds are 5 to 1 that she will win.她获胜的机会是五比一。
• Do you know the odds of winning the lottery once?你知道赢得一次彩票的几率多大吗？