VOA科学技术2024--Researchers Announce Successful Rhino Embryo Transfer

Researchers Announce Successful Rhino¹ Embryo² Transfer

　　Scientists in Berlin announced recently the first successful embryo transfer in a white rhinoceros³.

　　The transfer, which occurred in a southern white rhinoceros, offers hope for saving the northern white rhino from completely dying off.

　　Two kinds of white rhinoceros

　　The white rhinoceros includes two different subspecies, the northern and the southern. The last male northern white rhino died in 2018. Only two female members of the subspecies remain. Neither of them can carry a baby.

　　Southern white rhinos⁴ are more numerous.

　　Researchers hope to use eggs and sperm⁵ from northern white rhinos to produce embryos⁶ that will be put into southern white rhino surrogate mothers.

　　A surrogate is something that performs the duties of something else.

　　To test the plan, scientists said they transferred the embryo of a southern white rhino into a surrogate southern white rhino mother at the Ol Pejeta Conservancy in Kenya on September 24, 2023.

　　However, the research team only learned of the pregnancy⁷ after the surrogate mother died of a bacterial⁸ infection in November 2023. The embryo was discovered during an examination of the body after death.

　　Even with the death, researchers found reasons to be hopeful.

　　The international BioRescue team, a group backed by the German government, confirmed recently that the operation had produced a successful pregnancy of 70 days, with a well-developed 6.4-centimeter-long male embryo.

　　"We achieved together something which was not believed to be possible," said Thomas Hildebrandt of the Leibniz Institute for Zoo and Wildlife Research.

　　"That is really a milestone⁹ to allow us to produce northern white rhino calves¹⁰ in the next two, two and a half years," Hildebrandt said.

　　Too late?

　　The northern white rhinoceros subspecies has only two known examples left in the world. The Ol-Pejeta Conservancy in Kenya says that Najin, a 34-year-old, and her 23-year-old offspring, Fatu, both cannot naturally reproduce.

　　In 2018, the last male white rhino, Sudan, was 45 when he was euthanized because of age-related problems. He was Najin's father. Scientists stored his semen and that of four other dead rhinos.

　　Some conservation groups have argued that it is probably too late to save the northern white rhino using the method known as in vitro fertilization.

　　The species once lived in Chad, Sudan, Uganda, Congo and Central African Republic, but human conflict has caused the creature to disappear. Critics say the efforts made to save the northern white rhino should instead go to save at-risk species that have a better chance to survive.

　　About 20,000 southern white rhinos remain in Africa. That subspecies and another species, the black rhino, are increasing in number after illegal hunting nearly caused their disappearance¹¹.

　　Words in This Story

　　transfer – v. to move something from one place to another

　　subspecies – n. a group of related plants or animals that is smaller than a species

　　achieve –v. to do something that you were trying to do

　　milestone – n. an important point in the progress or development of something

　　euthanize – v. to put to death in a humane¹² way

　　in vitro –adj. (scientific) taking place in a laboratory or outside of normal biological methods

1 rhino   

n.犀牛，钱, 现金

参考例句：

• The rhino charged headlong towards us.犀牛急速地向我们冲来。
• They have driven the rhino to the edge of extinction.他们已经令犀牛濒临灭绝。

2 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

3 rhinoceros   

n.犀牛

参考例句：

• The rhinoceros has one horn on its nose.犀牛鼻子上有一个角。
• The body of the rhinoceros likes a cattle and the head likes a triangle.犀牛的形体像牛，头呈三角形。

4 rhinos   

n.犀牛（rhino的复数形式）

参考例句：

• There are many reports of people taming and even training Indian rhinos. 有许多关于人们驯养甚至训练印度犀牛的记载。 来自辞典例句
• The rhinos had fed during the night in the rice fields of these villagers. 犀牛夜里在这些村民的庄稼地里也已吃饱了。 来自辞典例句

5 sperm   

n.精子，精液

参考例句：

• Only one sperm fertilises an egg.只有一个精子使卵子受精。
• In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中，一个精子使一个卵子受精。

6 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

7 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。

8 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

9 milestone   

n.里程碑；划时代的事件

参考例句：

• The film proved to be a milestone in the history of cinema.事实证明这部影片是电影史上的一个里程碑。
• I think this is a very important milestone in the relations between our two countries.我认为这是我们两国关系中一个十分重要的里程碑。

10 calves   

n.(calf的复数)笨拙的男子，腓；腿肚子( calf的名词复数 )；牛犊；腓；小腿肚v.生小牛( calve的第三人称单数 )；（冰川）崩解；生（小牛等），产（犊）；使（冰川）崩解

参考例句：

• a cow suckling her calves 给小牛吃奶的母牛
• The calves are grazed intensively during their first season. 小牛在生长的第一季里集中喂养。 来自《简明英汉词典》

11 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

12 humane   

adj.人道的，富有同情心的

参考例句：

• Is it humane to kill animals for food?宰杀牲畜来吃合乎人道吗？
• Their aim is for a more just and humane society.他们的目标是建立一个更加公正、博爱的社会。