In the case of uncorrelated noises , it is shown that only the fluctuation of degradation reaction rate can induce a switch process , and the mean first passage time ( mfpt ) between the high concentration state and low concentration one is decreased when the noise intensity of degradation reaction rate is increased 可以看到源于蛋白質(zhì)基本合成率的噪聲強(qiáng)度不能引起基因狀態(tài)的轉(zhuǎn)變(即基因的開關(guān))而源于降解率噪聲強(qiáng)度則能夠?qū)崿F(xiàn)這種開關(guān)。當(dāng)進(jìn)一步研究在降解率波動作用下基因從一個態(tài)躍遷到另一個態(tài)的平均首通時間( mfpt )時可以看到此時隨著這個波動強(qiáng)度的增加, mfpt是單調(diào)遞減的。