cancer studies have shown that p53 can actually cause aging symptoms by killing too many cells when it goes into , but Serrano said his research strictly

　　the gene so that it turned on only when needed.

　　The gene did their job of producing a protein that kills damaged cancer cells. But the researchers found that mice with an extra copy of the genes This is the first anti-cancer gene tested for its effect on aging, Serrano said. The mice lived 16 percent longer in their average life span.

　　The p53 gene, when working properly,

　　If the gene is mutated or inactivated the control mechanism does not work.

　　Serrano also said that other research has shown that mice and worms that eat less have slower metabolisms and live longer. But his study offers evidence that

　　Section C

　　文章精要

　　本文主要介绍的是一项新的科学发现。有一种基因不仅能够抵抗癌细胞，还能够延缓衰老。科学家通过小白鼠实验发现，这种基因能降低癌症对它们身体的影响并且延长它们的寿命。虽然实验已证实吃得少能降低新陈代谢的速率，从而使小白鼠活得更久，然而得益于此种基因，它们能在不挨饿的情况下获得更长的寿命。

　　36.extending

　　37.genetically

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