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21英语教师网 > 备课资源 > 拓展阅读 > 正文
Make me a copy
作者:21ST    来源:高中版第164期     日期: 2010-12-14


关键词:Science, genetics, society

话题归类:科普知识与现代技术Popular science and modern technology


TWINS seem luckier as they have a very close friend from the moment they are born. Have you ever dreamt about having a brother or sister who looks exactly like you?

Now modern technology can make this possible. In 1997, Dolly the sheep (多莉羊) was the first mammal (哺乳动物) to be cloned from a single cell in 1997. Since then scientists have been working to explore more possibilities in the cloning world. Recently Chinese scientists have also successfully cloned mammals such as an ox.

But, the issue has caused a debate. The United Nations passed a declaration banning all forms of human cloning in February, saying it is contrary to human dignity (尊严). Supporters included the US and Germany. But not everyone agreed. China, Japan, Britain and another 32 countries believe limited cloning is helpful.

China is against cloning another person, but supports limited cloning research for the treatment and prevention of diseases.

Supporters of the research say it could lead to cures for cancer, diabetes (糖尿病) and other diseases.

What is Cloning?

Cloning is making a genetic (基因的) copy of something else. This might be copying just one cell, or it could be a whole animal. The biggest star of the cloning world is a sheep named Dolly. She is a copy of her mother. This means that she is the twin sister of her mother who was six years older and she did not have a father!

Our bodies are made up of cells, which hold information contained in DNA

or deoxyribonucleic acid (脱氧核糖核酸). Organisms (生物体) get half their DNA from the mum and half from their dad.

We all grow from a single cell, which contains these two parts of DNA. It is called the egg cell (胚胎细胞). It divides millions of times to give rise to the millions of cells, which form our body.

Each cell has a copy of all the genetic information needed by the body. This means that each cell of our body has enough information to create other human beings like us. All we need is an egg cell.

In the process of cloning, the scientists take out the DNA from an animal cell and put it into an egg cell taken from another animal. Before implanting (植入) it, the DNA of the recipient (受体) cell is removed.

This is how Dolly's life began - from a single cell taken from her mother. The DNA in her mother's cell was taken out and put into the egg cell of another sheep. Five months later, Dolly was born.

关键词:外研版 高二 Cloning 科普知识与现代技术Popular science and modern technology



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