劍橋雅思 17 閱讀原文翻譯 T2P2—A Second Attempt at Domesticating the Tomato

本篇文章共分 A-E 5 大段 (為配合題目出題，有些大段中包含 2-5 個小段)，從古代經歷不知幾代的番茄培育方式與成果，對比到今日在實驗室裡利用 CRISPR 技術可以在短短數年之中產生出理想糧食作物的神速奇效，展望到此種基因技術為人類更多選擇的未來所能提供的貢獻。

本篇考題英文原文與對應之中文翻譯整理如下。練習作答解題時若有對語意不清楚之處，請仔細查閱對照，以提升閱讀理解能力。

1. 基因技術突破糧食培育

   It took at least 3,000 years for humans to learn how to domesticate the wild tomato and cultivate it for food. Now two separate teams in Brazil and China have done it all over again in less than three years. And they have done it better in some ways, as the re-domesticated tomatoes are more nutritious than the ones we eat at present.

   This approach relies on the revolutionary CRISPR genome editing technique, in which changes are deliberately made to the DNA of a living cell, allowing genetic material to be added, removed or altered. The technique could not only improve existing crops, but could also be used to turn thousands of wild plants into useful and appealing foods. In fact, a third team in the US has already begun to do this with a relative of the tomato called the groundcherry.

   This fast-track domestication could help make the world’s food supply healthier and far more resistant to diseases, such as the rust fungus devastating wheat crops.

   ‘This could transform what we eat,’ says Jorg Kudla at the University of Munster in Germany, a member of the Brazilian team. ‘There are 50,000 edible plants in the world, but 90 percent of our energy comes from just 15 crops.’

   ‘We can now mimic the known domestication course of major crops like rice, maize, sorghum or others,’ says Caixia Gao of the Chinese Academy of Sciences in Beijing. ‘Then we might try to domesticate plants that have never been domesticated.’

   人類至少花了 3000 年時間才學會如何馴化野生番茄並將其栽培為食物。現在巴西和中國的兩個獨立團隊在不到三年的時間裡再次完成了這一工作。而且他們在某些方面做得更好，因為重新培育的番茄比我們現在吃的番茄更有營養。

   這種方法依賴於革命性的 CRISPR 基因組編輯技術，即故意對活細胞的DNA 進行改變，允許增添、刪除或改變遺傳物質。這項技術不僅可以改進現有的作物，而且還可以用來把成千上萬的野生植物變成有用和有吸引力的食物。事實上，美國的第三個研究團隊已經開始對番茄的一個親戚—酸漿果進行這種研究。

   這種快速的培育可以幫助使世界的糧食供應更加發達，對疾病的抵抗力大大增強，例如破壞小麥作物的銹病真菌。

   “這可以改變我們的飲食，” 巴西團隊成員、德國明斯特大學的 Jorg Kudla 說。“世界上有 5 萬種可食用的植物，但我們 90% 的能量僅來自15 種作物。”

   北京中國科學院的高彩霞說：“我們現在可以模仿主要作物如水稻、玉米、高粱或其他作物的已知培育過程。然後我們可能會嘗試培育那些從未被培育過的植物。”

2. 早期人工培育

   Wild tomatoes, which are native to the Andes region in South America, produce pea-sized fruits. Over many generations, peoples such as the Aztecs and Incas transformed the plant by selecting and breeding plants with mutations* in their genetic structure, which resulted in desirable traits such as larger fruit.

   But every time a single plant with a mutation is taken from a larger population for breeding, much genetic diversity is lost. And sometimes the desirable mutations come with less desirable traits. For instance, the tomato strains grown for supermarkets have lost much of their flavour. By comparing the genomes of modern plants to those of their wild relatives, biologists have been working out what genetic changes occurred as plants were domesticated. The teams in Brazil and China have now used this knowledge to reintroduce these changes from scratch while maintaining or even enhancing the desirable traits of wild strains.

   野生番茄，原產於南美洲安第斯山脈地區，生產豌豆大小的果實。經過多代人的努力，阿茲特克人和印加人等民族通過選擇和培育在遺傳結構上有突變的植物來改造這種植物，從而產生了理想的特性，如更大的果實。

   但是，每當從大型種群中抽取一株有突變的植物進行育種時， 就會失去很多遺傳多樣性。有時，理想的突變會帶來不太理想的特性。例如，為超市種植的番茄品系已經失去了大部分的味道。通過將現代植物的基因組與它們的野生親屬的基因組進行比較，生物學家一直在研究植物被培育時發生了哪些遺傳變化。巴西和中國的研究團隊現在已經利用這些知識從頭開始重新引入這些變化，同時保持甚至加強野生品系的理想特性。

3. 新式培育效果顯著

   Kudla’s team made six changes altogether. For instance, they tripled the size of fruit by editing a gene called FRUIT WEIGHT, and increased the number of tomatoes per truss by editing another called MULTIFLORA.

   While the historical domestication of tomatoes reduced levels of the red pigment lycopene – thought to have potential health benefits – the team in Brazil managed to boost it instead. The wild tomato has twice as much lycopene as cultivated ones; the newly domesticated one has five times as much.

   ‘They are quite tasty,’ says Kudla. ‘A little bit strong. And very aromatic.’ The team in China re-domesticated several strains of wild tomatoes with desirable traits lost in domesticated tomatoes. In this way they managed to create a strain resistant to a common disease called bacterial spot race, which can devastate yields. They also created another strain that is more salt tolerant – and has higher levels of vitamin C.

   庫德拉的團隊總共做了六項改變。例如，他們通過編輯一個名為FRUIT WEIGHT 的基因，使果實的大小增加了兩倍，並通過編輯另一個名為 MULTIFLORA 的基因，增加了每個桁架的番茄數量。

   雖然歷史上對番茄的培育降低了紅色素的含量—人們認為它對健康有潛在的好處—但巴西的研究小組反而設法提高了它的數值。野生番茄的番茄紅素含量是栽培番茄的兩倍；新培育的番茄則是五倍。

   “它們相當美味，” 庫德拉說。“味道有一點重。而且香氣十足。” 中國的研究小團隊重新培育了幾個野生番茄品系，這些品系具有在培育的番茄中失去的理想特性。通過這種方式，他們成功地創造了一個能抵抗一種叫做細菌性斑點病的常見疾病的品系，這種疾病會破壞產量。他們還創造了另一個更耐鹽的品系，並具有更高的維生素C 含量。

4. 其他作物培育

   Meanwhile, Joyce Van Eck at the Boyce Thompson Institute in New York state decided to use the same approach to domesticate the groundcherry or goldenberry (Physalis pruinosa) for the first time. This fruit looks similar to the closely related Cape gooseberry (Physalis peruviana).

   Groundcherries are already sold to a limited extent in the US but they are hard to produce because the plant has a sprawling growth habit and the small fruits fall off the branches when ripe. Van Eck’s team has edited the plants to increase fruit size, make their growth more compact and to stop fruits dropping. ‘There’s potential for this to be a commercial crop,’ says Van Eck. But she adds that taking the work further would be expensive because of the need to pay for a licence for the CRISPR technology and get regulatory approval.

   與此同時，紐約州博伊斯-湯普森研究所的喬伊絲-范-埃克決定使用同樣的方法首次培育酸漿果或燈籠果（Physalis pruinosa）。這種水果看起來與密切相關的開普敦鵝莓（Physalis peruviana）相似。

   酸漿果已經在美國有限度地銷售，但它們很難生產，因為這種植物有一個蔓延的生長習性，小果實成熟後會從樹枝上掉下來。范-埃克的團隊已經對植物進行了編輯，以增加果實的大小，使其生長更加緊湊，並阻止果實掉落。范-埃克說：“這有可能成為一種商業作物。” 但她補充說，由於需要支付 CRISPR 技術的許可證並獲得監管部門的批准，進一步開展這項工作的成本很高。

5. 新式培育的經濟發展性

   This approach could boost the use of many obscure plants, says Jonathan Jones of the Sainsbury Lab in the UK. But it will be hard for new foods to grow so popular with farmers and consumers that they become new staple crops, he thinks.

   The three teams already have their eye on other plants that could be ‘catapulted into the mainstream’, including foxtail, oat-grass and cowpea. By choosing wild plants that are drought or heat tolerant, says Gao, we could create crops that will thrive even as the planet warms.

   But Kudla didn’t want to reveal which species were in his team’s sights, because CRISPR has made the process so easy. ‘Any one with the right skills could go to their lab and do this.’

   英國森寶利實驗室的強納森-瓊斯說，這種方法可以促進許多不知名的植物的使用。但他認為，新的食物將很難受到農民和消費者的歡迎，以至於成為新的主食作物。

   這三個團隊已經注意到了其他可以 “進入主流” 的植物，包括狐尾草、燕麥草和豇豆。高彩霞說，通過選擇耐旱或耐熱的野生植物，我們可以創造出即使在地球變暖時也能茁壯成長的作物。

   但是 Kudla 不想透露哪些物種在他團隊的視線當中，因為 CRISPR 已經使得此過程變得如此簡單。“任何一位擁有正確技能的人都可以去到他們的實驗室並完成任務。”