what is a mutagen
A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. A Mutagen is an agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed. Once the gene has been damaged or changed the mRNA transcribed from that gene will now carry an altered message.
Any agent that promotes a mutation or causes an increase in the rate of mutational events, e.g., radioactive substances, x-rays, or certain chemicals. mutagen. Any agent capable of changing the structure of DNA without immediately killing the cell concerned.