它们可以附在胞核嘧啶上，胞核嘧啶是组成基因代码的“字母”的四种碱基数之一，帮助调控转录的过程。

These can attach themselves to cytosine , one of the four chemical bases that form the "letters" of the genetic code.

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正如查尔斯·达尔文（Charles Darwin）所观察到的那样，只要有一种基因组成的个体比其他个体更善于繁殖，自然选择就会起作用。

As Charles Darwin observed, natural selection operates whenever individuals of one genetic composition are better at reproducing than that of others.

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一群成千上万的白杨实际上可以组成一个单独的有机体，被称为克隆，它们共享一个相互连接的根系和一套独特的基因。

A group of thousands of aspens can actually constitute a single organism, called a clone, that shares an interconnected root system and a unique set of genes.

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The goal of that was to take for a typical human, or for a typical - in the case of the human genome project maybe you're looking at fruit flies, you want to look at all the DNA in a fruit fly, but to look at the sequence of base pairs that makes up human DNA and write them all out; we'll talk about that later.

这个计划的目的是,建立一个有代表性人类的基因顺序,或者说是典型的人类基因组,就人类基因组计划来说,或许你在研究果蝇,你想观察果蝇内的所有DNA,而人类基因组计划是观察组成人类的,DNA的碱基对顺序并且将它们记录下来,我们不久之后会讨论这些内容

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