Barbeyron T, Kean K, Forterre P
J Bacteriol. 1984 Nov;160(2):586-90. doi: 10.1128/jb.160.2.586-590.1984.
We have examined the presence of methylated adenine at GATC sequences (Dam phenotype) in the DNA of 23 eubacteria and 13 archaebacteria by using isoshizomer restriction enzymes. We have found a completely Dam+ phenotype in bacteria of nine genera related to the families Enterobacteriaceae, Parvobacteriaceae, and Vibrionaceae, and in the five cyanobacteria tested. We have found a partial Dam+ phenotype in the two archaebacteria Halobacterium saccharovorum and Methanobacterium sp. strain Ivanov. All of the other archaebacteria (three genera) and eubacteria (nine genera) tested were Dam-. Phylogenetic analysis, based on the evolutionary tree of Fox et al. (Science 209:457-463, 1980), indicates that dam methylation in the Escherichia coli lineage appeared recently in bacterial evolution and is restricted to a small range of closely related bacteria.
我们利用同裂酶限制酶检测了23种真细菌和13种古细菌DNA中GATC序列处甲基化腺嘌呤的存在情况（Dam表型）。我们在与肠杆菌科、细小杆菌科和弧菌科相关的9个属的细菌以及所检测的5种蓝细菌中发现了完全的Dam+表型。我们在两种古细菌——嗜盐糖杆菌和伊凡诺夫甲烷杆菌菌株中发现了部分Dam+表型。所有其他检测的古细菌（3个属）和真细菌（9个属）均为Dam-。基于福克斯等人（《科学》209:457 - 463, 1980）的进化树进行的系统发育分析表明，大肠杆菌谱系中的dam甲基化在细菌进化过程中是最近出现的，并且仅限于一小范围密切相关的细菌。
