How does ethidium bromide cause mutations?

Ethidium bromide causes mutations by intercalating with DNA.

Ethidium bromide is a flat, planar molecule with a ring structure that resembles a DNA base pair. The unique structure of EtBr allows the molecule to insert itself or intercalate between stacked bases in double-stranded DNA. In doing so, it uncoils the DNA deforming its structure and interferes with DNA transcription, replication, recombination, and repair, causing different types of mutations.