雅思課外閱讀：雙語科學(xué)篇之克隆

很多同學(xué)做了一些雅思的閱讀題發(fā)現(xiàn)分?jǐn)?shù)還是上不去，這里老師想給大家一些建議，平時應(yīng)該多關(guān)注一些與雅思考試難度類似的英文讀物，多讀多看，相信大家長期堅持下來，閱讀一定會有一個質(zhì)的飛躍；今天老師就給大家推薦一篇雅思課外閱讀：雙語科學(xué)篇之克隆，供同學(xué)們參考學(xué)習(xí)。

Cloning克隆

Nearly all living organisms have parents in which they were reproduced and born through various stages of the life cycle. Whether it is a human being with a mother and a father or a chicken hatching from an egg, most living organisms have male and female parents. Some living organisms also form from one parent such as when a single-celled amoeba splits into two to reproduce offspring.

幾乎所有的生命體在生命周期的不同階段都有雙親孕育和培養(yǎng)。無論是有父母雙親的人類還是從一只從雞蛋孵化而成的雞，大部分生命體有兩性親代。也有一些生物體形成于單一親代，例如單細(xì)胞變形蟲分裂成兩個從而繁衍后代。

However, there is a process which is much different in producing offspring called cloning. Cloning is the process when scientists take DNA from an animal cell and then place it or implant it into an egg cell taken from another animal. Before placing though, the DNA from the cell receiving it is removed.

然而，克隆這種繁殖后代的方法大相徑庭?？寺∈强茖W(xué)家在動物細(xì)胞提取DNA然后將其放入或植入其他動物卵細(xì)胞的過程。在植入之前，受體細(xì)胞內(nèi)的DNA被移除。

An example of cloning, which made history in 1997, was when scientists successfully cloned a sheep. The new sheep's name was Dolly, and she was not born in the usual manner. Instead, she became an exact copy of her mother, similar to an identical twin. It would be nearly the same as taking the DNA from the son of a mother, placing the DNA in the egg cell of another woman, but first removing the woman's own DNA, and then allow the growth of the new cell in the woman. Nine months later there would be an exact copy of the mother's son born to the woman.

克隆史上的首例是科學(xué)家在1997年成功克隆羊。取名為多莉的克隆羊以非常規(guī)方式孕育而成。然而，她與其母本完全一致，類似于同卵雙生。這與采集兒子母親的DNA后放入另一個女人的已除去其本身DNA的卵細(xì)胞中，然后新細(xì)胞的在女人體內(nèi)生長。九個月后女人便產(chǎn)下與其兒子母親完全一致的男嬰。

In the case of cloning, a father is not needed. In the first successful cloning of an animal the DNA molecule had all of the information needed to create a clone, Dolly. The DNA molecules contains the genetic code, which is basically directions for the new offspring. Normally, a new organism gets half of this code from the father and the other half from the mother. When these two cells are joined together they divide millions of times and then grow into the millions of cells which form the body of the animal. Each cell of the body has a copy of the genetic code and all it would need is an egg cell to grow.

克隆不需要父本。第一個成功的動物克隆中，DNA分子攜帶了克隆羊多莉所需的所有信息。 DNA分子中包含的遺傳密碼基本就是新生子代的方向。通常一個新的有機體得到父母親雙方各一半的遺傳密碼。兩個生殖細(xì)胞結(jié)合后經(jīng)過上百萬次分裂生成數(shù)百萬個細(xì)胞，構(gòu)成了動物體。體內(nèi)每一個細(xì)胞都復(fù)制了遺傳密碼，而它所需要的不過是孕育其生長的卵細(xì)胞。

So with cloning one of those cells is used and then the cell is simply placed in to the egg cell of the carrier. In the sheep example, the carrier was a female sheep. For Dolly, a single cell was used from the udder of her mother. The DNA in her mother's cell was removed and then transferred to an egg cell of another sheep. About five months later Dolly was born without a father and a copy or clone of her mother.

因此克隆就是將親本的體細(xì)胞中的一個植入載體的卵細(xì)胞中。利用多莉母親的乳房的一個細(xì)胞，將該細(xì)胞的DNA移植到另一只羊的卵細(xì)胞。大約五個月后，沒有父親的多莉出生，與其母親完全一致，是其母的克隆。

Though no humans have ever been fully cloned, human embryos have been cloned. Currently it may not be taking place, but in the future it may happen, but today it is rare. In the movies about Jurassic Park, cloning took place to create the dinosaurs, though it was a fictional movie, much of the science behind the process can be real.

雖然沒有完全的克隆人，但曾有克隆的人類胚胎?？寺∪四壳半y以實現(xiàn)，但將來卻可能成真，但至今仍然罕見。侏羅紀(jì)公園的電影中，克隆用于創(chuàng)造恐龍，雖然這是一個虛構(gòu)的電影，該過程后的科學(xué)大多是真實的。

Though there are fully developed human clones, other fully developed animals have been cloned besides sheep. They include the rhesus monkey, pig, cattle, cat, rabbit, deer, horse, a few others, and of course mice. Cloning also involves many, many failed attempts before it becomes successful. For instance, Dolly the sheep was not born until after 276 failed attempts. The only true successful cloning takes place when identical twins are born, but they came from a father and a mother. The cloned animals may also experience health problems.

盡管有發(fā)育完全的人類克隆，除了多莉羊外其他發(fā)育完全的動物克隆，如獼猴，豬，牛，貓，兔，鹿，馬等等，當(dāng)然也有老鼠?？寺〕晒η斑€有很多失敗的嘗試。例如，多莉是276失敗的嘗試后才出生的。唯一真正成功的克隆是同卵雙胞胎，但他們是源于同父同母?？寺游镆部赡軙馐芙】祮栴}。

In summary, cloning is basically creating another organism without the father involved, and the clone is an exact copy of the mother with the same genetic code. However, if cloning ever became 100% successful, the clones may look alike, but it would not mean they would behave in the same way.

總之，克隆基本上就是不需要父方生育后代且后代完全復(fù)制起母親。但是，100％成功的克隆，即使外表相似，但并不意味著它們的行為會一致。

以上就是雅思課外閱讀：雙語科學(xué)篇之克隆的詳細(xì)內(nèi)容，希望對大家的英語學(xué)習(xí)有所幫助！

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