Six months later, it moves back. When the mutations are gradual, as with seasonal flu, it is known as drift; when they are abrupt, as with the new strain of H1N1, you have a shift on your hands.

如果病毒突变是渐进式的，就像季节性流感一样，就是为人所知的一般缓慢趋势，但如果病毒突变是急进式的，就像现在的H1N1新品种，那大家可就碰上了紧急的加速档了。

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When the mutations are gradual, as with seasonal flu, it is known as drift; when they are abrupt, as with the new strain of H1N1, you have a shift on your hands.

季节性流感的变异较缓和，被称为渐变；当像H1N1这样的新型病毒株发生变异的时候，这就是突变了。

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Most of these mutations are known as "passengers" and cause damage but not cancer.

这些突变基因中的大部分被认为是“乘客”，它们虽会造成破坏，却并不直接致癌。

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Over time,genes develop changes, known as mutations.

VOA: special.2010.02.02

Some have no real effect, and are known as silent mutations.

ECONOMIST: Genetics gets more complicated

Such mutations, known as neutrino oscillations, were hinted at three years ago by results from Super-Kamiokande, an older apparatus in Japan.

ECONOMIST: The news that neutrinos have mass is both good and bad

Similarly, Erivedge targets cancers in patients with mutations in a specific gene known as PTCH1.

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