迄今为止，不少人认为5-甲基胞嘧啶的存在可能是基因突变的热点。然而，事实上5-甲基胞嘧啶作为一种稀有碱基，本来就是许多真核生物DNA的正常组分。
5-methylcytosine ( m5C ) as a rare base exists in eucaryotic genomes , it is a normal constituent of many eucaryotic DNA , whose existence is a character of eucaryotic DNA .
稀有碱基