What are mutagenic agents?

The Mutagenic agents, or mutagens, are physical, chemical or biological factors that can cause alteration in DNA molecules.

Instances of believed or well-known to be mutagenic agents are: X, alpha, beta and gamma rays, ultraviolet radiation, nitrous acid, many dyes, some sweeteners, some herbicides, many substances of tobacco, some viruses, like HPV, and so on. Small DNA fragments called as transposons can also act as mutagens when incorporated into other DNA molecules.