VOA慢速英语--新发现的骨骼显示古人类的基因组合

Newly Discovered Bones Show Genetic¹ Mix of Ancient Human Relatives

Scientists say they have discovered the remains² of an ancient female whose mother was a Neanderthal and whose father was Denisovan.

Neanderthals and Denisovans are early human species that have been extinct for thousands of years. The discovery marks the first time scientists have found the remains of a child created by these two kinds of early humans.

The researchers found the 90,000-year-old pieces of bone in southern Siberia. The team published their findings in the journal Nature on Wednesday.

Why the discovery is important

Neanderthals lived in Europe and Asia. Remains of Denisovans are known only from the cave where the bone was found. Both groups disappeared by about 40,000 years ago.

Past genetic studies have shown evidence of sexual relations between the two groups, as well as with our own species, Homo sapiens. The unions show in the genetic structure, or DNA³, of today’s people. But the new study is the first to identify a first-generation child with Neanderthal and Denisovan parents.

Svante Paabo is one of the lead researchers of the study. He is a geneticist at the Max Planck Institute for Evolutionary⁴ Anthropology⁵ in Leipzig, Germany. Paabo said he was surprised the bones were found. Both Neanderthal and Denisovan remains are rarely discovered anywhere in the world. So finding an actual child of the two groups seemed like unusually good luck, Paabo said.

The discovery is also interesting because the two groups were more different from each other than any two present-day human groups.

“The fact that we stumbled across this makes you wonder if the mixing wasn’t quite frequent,” said Paabo,

Other opinions

Ron Pinhasi is a physical anthropologist⁶ at the University of Vienna who was not involved in the study. He noted⁷ that the discovery does not answer how often Neanderthals and Denisovans mated. If they mated often, he said, the DNA of Neanderthals and Denisovans would not show such major differences.

Anders Eriksson is an evolutionary population geneticist at King’s College London who was not involved in the study either. He suggested that the DNA could be looked at in several different ways.

“I think they convincingly showed that genetically⁸ this individual falls halfway⁹ between the Neanderthal and Denisovan fossils found in the same cave,” said Eriksson. “But I’m less convinced that it is necessarily a first-generation offspring of a … Neanderthal and Denisovan.”

The fossil could instead have come from a population with nearly an equal mix of Neanderthal and Denisovan relatives, he observed. And it will take studies of more fossils to find this out.

What else can we learn?

The authors of this week’s report said the small pieces of bone likely came from the arm or leg of a female who was at least 13 years old at the time of death. They call her “Denisova 11.”

The researchers compared her DNA with other ancient DNA. They learned that the genes¹⁰ from her mother were more closely related to Neanderthals who lived later in Europe than other Neanderthal remains from the cave.

This finding suggests that Neanderthals moved westward¹¹ over time.

Svante Paabo said the latest discovery suggests that the now-extinct ancient relatives of humans were not killed off by warfare¹², as many experts believe. Instead, it supports a theory that our ancient relatives combined with modern humans through sexual relationships.

I’m Pete Musto.

Words in This Story

species – n. a group of animals or plants that are similar and can produce young animals or plants

extinct – adj. no longer existing

journal – n. a magazine that reports on things of special interest to a particular group of people

cave – n. a large hole that was formed by natural processes in the side of a cliff or hill or under the ground

union(s) – n. an act of joining two or more things together

stumble(d) across – p.v. to discover something accidently

quite – adv. to a very noticeable degree or extent

frequent – adj. happening often

mate(d) – v. o have sexual activity in order to produce young

convincingly – adv. done in a way that causes someone to believe that something is true or certain

fossil(s) – n. something, such as a leaf, skeleton, or footprint, that is from a plant or animal which lived in ancient times and that you can see in some rocks

offspring – n. a person's child

author(s) – n. a person who has written something

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 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。

4 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

5 anthropology   

n.人类学

参考例句：

• I believe he has started reading up anthropology.我相信他已开始深入研究人类学。
• Social anthropology is centrally concerned with the diversity of culture.社会人类学主要关于文化多样性。

6 anthropologist   

n.人类学家，人类学者

参考例句：

• The lecturer is an anthropologist.这位讲师是人类学家。
• The anthropologist unearthed the skull of an ancient human at the site.人类学家在这个遗址挖掘出那块古人类的颅骨。

7 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

8 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

9 halfway   

adj.中途的，不彻底的，部分的；adv.半路地，在中途，在半途

参考例句：

• We had got only halfway when it began to get dark.走到半路，天就黑了。
• In study the worst danger is give up halfway.在学习上，最忌讳的是有始无终。

10 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

11 westward   

n.西方，西部；adj.西方的，向西的；adv.向西

参考例句：

• We live on the westward slope of the hill.我们住在这座山的西山坡。
• Explore westward or wherever.向西或到什么别的地方去勘探。

12 warfare   

n.战争(状态)；斗争；冲突

参考例句：

• He addressed the audience on the subject of atomic warfare.他向听众演讲有关原子战争的问题。
• Their struggle consists mainly in peasant guerrilla warfare.他们的斗争主要是农民游击战。