What is a mutation?

What is a mutation?

• A. A non-heritable change in a trait caused by the environment.
• B. A heritable change in DNA that creates new genetic variation.
• C. A heritable change in DNA that introduces new genetic variation essential for natural selection to act upon.
• D. A change that immediately increases an organism's survival in all environments.

Answer: (C)

A mutation is a heritable change in the DNA sequence that introduces new genetic variation for a population, providing the material natural selection can act upon. Mutations can happen spontaneously or due to mutagens, and only changes in germ cells are passed to offspring. Most mutations have little effect, some are harmful, and a few are beneficial in a given environment. Because natural selection operates on the variation present in a population, the ability of mutations to create new alleles is essential for evolutionary change. That’s why this option represents the best answer: it ties the idea of a DNA change to the creation of variation and to how evolution proceeds. It’s not correct to say mutations always boost survival in all environments, since many mutations are neutral or deleterious, and their fitness effects depend on context.

A mutation is a heritable change in the DNA sequence that introduces new genetic variation for a population, providing the material natural selection can act upon. Mutations can happen spontaneously or due to mutagens, and only changes in germ cells are passed to offspring. Most mutations have little effect, some are harmful, and a few are beneficial in a given environment. Because natural selection operates on the variation present in a population, the ability of mutations to create new alleles is essential for evolutionary change. That’s why this option represents the best answer: it ties the idea of a DNA change to the creation of variation and to how evolution proceeds. It’s not correct to say mutations always boost survival in all environments, since many mutations are neutral or deleterious, and their fitness effects depend on context.