Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

2. Due to changes in the sequence of nitrogen bases

Explanation:

A gene mutation can be defined as a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size. They can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. Gene mutation does not occur due to reproduction, linkage or changes in the size of the DNA.