How does mutation relate to variation

Mutation is the source for new genetic variation: Genetic variation is brought about by random mutation. Without mutation, genetic variation cannot occur. Mutation is a change in the genetic code in DNA and can lead to a change in the protein that is coded for that segment of DNA.

Explanation:

Mutations are changes to an organism's DNA and are an important driver of diversity in populations. Species evolve because of the accumulation of mutations that occur over time ... This mutation has introduce a new allele into the population that increases genetic variation and may be passed on to the next generation.