英语翻译Cloning has always been with us and is here to stay.It is a way of making an exact copy of another animal or plant.It happens in plants when gardeners take cuttings from growing plants to make new ones.It also happens in animals when tein

英语翻译Cloning has always been with us and is here to stay.It is a way of making an exact copy of another animal or plant.It happens in plants when gardeners take cuttings from growing plants to make new ones.It also happens in animals when tein
英语翻译
Cloning has always been with us and is here to stay.It is a way of making an exact copy of another animal or plant.It happens in plants when gardeners take cuttings from growing plants to make new ones.It also happens in animals when teins idrntical in sex and appearance are produced from the same original egg.The fact is that these are both examples of natural clones.
Cloning has two major uses.Firstly,gardeners use it all the time to produce commercial quantities of plants.Secondly,it is valuable for research on new plant species and for medical research on animals.Cloning plants is straightforward while cloning animals is very complicated.
It is a difficult task to undertake.Many attempts to clone mammals failed.But at last the determination and patience of the scientists paid off in 1996 with a breakthrough— the cloning of Dolly the sheep.The procedure works like this:
1 Female sheep A provides an egg cell.
2 The nucleus is removed from the egg cell.
3 The egg cell is ready for a new nucleus.
4 Female sheep B provides a somatic cell for the clone.The nucleus of this cell contains all the genes needed to produce a new sheep.
5 The nucleus is taken out of the somatic cell.
6 The nucleus from sheep B and the egg cell from sheep A are joined using electricity.
7 The cell divides and grows into an embryo.
8 The embryo is put into female sheep C,who becomes the carrier of the clone.
9 The lamb is the clone of the donated cell from sheep B which provided the nucleus.

英语翻译Cloning has always been with us and is here to stay.It is a way of making an exact copy of another animal or plant.It happens in plants when gardeners take cuttings from growing plants to make new ones.It also happens in animals when tein
克隆一直在我们左右并且已经被大多数人接受.它是一种用来准确复制其他动物或者植物的方法.在植物方面,克隆就发生在园丁从正在生长的植物上切去切口用来制造新的植株的时候.在动物方面也有克隆现象,比如说两个拥有同样性别以及外貌的同卵双胞胎.这两个事实都是自然界里的克隆例子.
克隆有2方面的主要用途.首先,园丁可以一直用它生产具有商业价值的植物.其次,它对于新的植物物种以及动物医药方面的研究极具价值性.植物克隆相对于动物克隆来说简单得多,而动物克隆则比较困难.
动物克隆是一项难以施行的任务.许多去克隆哺乳动物的尝试都以失败告终.但是在最后,科学家们凭借着决心和耐心终于在1996年取得了突破性的成功——成功地克隆出了多利羊.这项工作的步骤如下：
1.从母羊A体内取出卵细胞.
2.将细胞核从该卵细胞中移除.
3.该卵细胞为另一个新的细胞核准备.
4.从母羊B体内取出体细胞用于克隆.该体细胞内的细胞核包含了克隆一只新的羊所需的全部基因.
5.将该细胞核从体细胞中取出.
6.用电激的方法将从母羊B体内取出的细胞核与从母羊A体内取出的卵细胞融合.
7.重新融合的细胞在胚胎内分裂、生长.
8.将胚胎植入母羊C的体内,它将成为该克隆的携带者.
9.克隆出来的小羊羔体内细胞的基因来自于提供细胞核的母羊B.