Answer:
A gene mutation refers to a permanent change in the sequence of DNA, which forms a gene, that is, the sequence varies from what is witnessed in the majority of the individuals. The mutations vary in size, they can influence anywhere from a base pair to a huge section of a chromosome, which comprises multiple genes.
The mutations result in extreme modifications in a species if they modify the manner in which a protein functions. However, a mutation, which directs the formation of altered proteins or the unexpected amounts of proteins is the most general way by which a mutation contributes to disease.