According to research, DNA methylation in bacteria regulates virulence, reproduction, and gene expression. DNA methylation is crucial for controlling the tissue-specific gene expression that determines a cell's identity, such as whether it is a skin cell or a brain cell, in other creatures, including humans. The findings of the research were published in the journal 'Genome Biology'. One way cells can control the activities of their genes is by adding small chemical modifications to the DNA that determine which genes are turned on or off. Methyl groups are one of these chemical modifications or tags.