Variation in a trait may be due to the change in genetic material. What do you call this type of change?

The correct answer is: Mutation

DNA or the genetic material is made of sequence of nucleic acids. A particular length of nucleic acids code for a particular trait and is called gene.
Due to failure of "proof reading activity" of DNA during replication or due to environmental factors, the normal sequence of nucleic acids is altered. This phenomenon is called mutation.
The mutation can be beneficial or harmful to the individual. Sometimes, the change in nucleic acids do not have any effect and is called silent mutation.

• DNA is the genetic material for all organisms
• DNA is made of sequence of nucleic acids
• Gene is the unit of heredity and codes for particular trait
• Change in sequence of nucleic acid is called mutation
• Not all mutations are harmful