Montero L M, Filipski J, Gil P, Capel J, Martínez-Zapater J M, Salinas J
Dpto. de Protección Vegetal, INIA, Madrid, Spain.
Nucleic Acids Res. 1992 Jun 25;20(12):3207-10. doi: 10.1093/nar/20.12.3207.
We have determined the 5-methylcytosine (5mC) content in high molecular weight DNA, from two dicot (tobacco and pea) and two monocot (wheat and maize) plant species, fractionated according to base composition. The results show that the proportion of 5mC in the genomic fractions increases linearly with their guanine + cytosine (G + C) content while the proportion of non-methylated cytosine remains almost constant. This can be interpreted as a consequence of a difference in mutation pressure related to spontaneous deamination of 5mC to thymine between the different compartments of plant genomes.
我们已经测定了来自两种双子叶植物(烟草和豌豆)和两种单子叶植物(小麦和玉米)的高分子量DNA中的5-甲基胞嘧啶(5mC)含量,这些DNA根据碱基组成进行了分级分离。结果表明,基因组级分中5mC的比例随鸟嘌呤+胞嘧啶(G + C)含量呈线性增加,而非甲基化胞嘧啶的比例几乎保持不变。这可以解释为植物基因组不同区域之间与5mC自发脱氨形成胸腺嘧啶相关的突变压力差异的结果。