and acridine orange
are two important dyes. A direct attachment of these dyes to nucleic acids perhaps causes mutations. Other biological effects include elimination of nonchromosomal elements like F factor in bacteria by acriflavin.
Among acridine dyes, acriflavin is mutagenic for bacteria and higher plants like Allium
and proflavin has been shown to be mutagenic for phages. The molecular mechanism of their action is not fully understood. Acridine orange and other acridines stack along nucleic acids. They apparently attach to phosphate backbone. It is usually suggested that acridines induce only deletions and insertions of single base pair in DNA. Deletions and additions of base pairs cause shift in the framework, in which the nucleotide sequences are read by protein synthesizing machinery of the cell, using the genetic code dictionary. Such mutations are called frame-shift mutations,
which are discussed in relatively greater detail in The Genetic Code
on the Genetic Code.