N 6-methyladenine (6mdA) is a widespread DNA modification in bacteria. More recently,
6mdA has also been characterized in mammalian DNA. However, measurements of 6mdA
abundance and profiles are often very dissimilar between studies, even when performed on
DNA from identical mammalian cell types. Using comprehensive bioinformatics analyses of
published data and novel experimental approaches, we reveal that efforts to assay 6mdA in
mammals have been severely compromised by bacterial contamination, RNA …