VOA慢速英语2021--美国科学家宣布首次成功克隆濒危动物

American scientists recently announced the first cloning of an endangered animal native to the United States. A black-footed ferret was created from the cells of an animal that died over 30 years ago.

Officials from the U.S. Fish and Wildlife Service said the ferret, named Elizabeth Ann, was born December 10. She is a genetic¹ reproduction of a black-footed ferret named Willa who died in 1988. Willa's remains² were frozen in the early days of genetic technology.

Such use of cloning aims to one day bring back animal species that have died out. The black-footed ferret project is part of a wider effort to build up the population of the endangered animal.

Noreen Walsh is the director of the National Black-footed Ferret Conservation Center in Northern Colorado. The center is part of the Fish and Wildlife Service. In announcing the successful cloning, she said in a statement "it provides a promising³ tool for continued efforts to conserve⁴ the black-footed ferret."

Black-footed ferrets are easily recognized by the dark markings on their feet and around the eyes. They hunt and feed on prairie dogs.

Even before the cloning, the animals were a conservation success story. They were thought to have died out because of the loss of prairie dog populations they depend on. The prairie dogs were shot and poisoned by animal farmers seeking to create a better land environment for raising cows.

But in 1981, a black-footed ferret was discovered in the state of Wyoming. Scientists then gathered the remaining population for a captive mating program. Thousands of ferrets have been released in the western U.S., Canada and Mexico since the 1990s.

But a lack of genetic diversity presents an ongoing⁵ risk to the population. All ferrets brought back so far came from just seven closely related animals. This genetic similarity puts the ferrets at risk for developing serious health problems.

When Willa died, the Wyoming Game and Fish Department sent her tissues to a "frozen zoo" operated by San Diego Zoo Global. The zoo keeps cells from more than 1,100 species and subspecies worldwide.

In the future, scientists hope to make changes to those genes⁶ to help cloned animals survive.

"With these cloning (methods), you can basically freeze time and regenerate⁷ those cells," said Pete Gober. He leads the black-footed ferret recovery effort for the Fish and Wildlife Service. He added that while reaching that level of genetic engineering might take a long time, he is hopeful it will be possible.

Words in This Story

clone – v. to make an exact copy of a person, animal or plant

species – n. a group of animals or plants that are similar

conserve – v. to protect animals, plants and natural resources

diversity – n. a situation in which many different kinds of things or people are included in something

regenerate – v. form or create again

1 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。

2 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

3 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

4 conserve   

vt.保存，保护，节约，节省，守恒，不灭

参考例句：

• He writes on both sides of the sheet to conserve paper.他在纸张的两面都写字以节省用纸。
• Conserve your energy,you'll need it!保存你的精力，你会用得着的！

5 ongoing   

adj.进行中的，前进的

参考例句：

• The problem is ongoing.这个问题尚未解决。
• The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。

6 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

7 regenerate   

vt.使恢复，使新生；vi.恢复，再生；adj.恢复的

参考例句：

• Their aim is to regenerate British industry.他们的目的是复兴英国的工业。
• Although it is not easy,you have the power to regenerate your life.尽管这不容易，但你有使生活重获新生的能力。