5% of the genes and/or EST contained on our microarray being susceptible to the roughly 4-fold enhanced DNA methyltransferase activity conferred by Dnmt3amERe, which is reminiscent of the finding that the methylation-status of the vast majority of CpG islands in SV40-transformed human fibroblasts was unaffected despite 50-fold overexpression of Dnmt1 (Feltus et al. 2003).