What defines a mutation in genetic terms?

In genetic terms, a mutation is defined as a permanent change in the genetic sequence of an organism's DNA. This change can affect a single nucleotide pair or larger segments of DNA, impacting genes and potentially altering the organism's characteristics. Mutations can arise through various mechanisms, including spontaneous errors during DNA replication or as a result of environmental influences, but what defines them is their permanence and the fact that they can be inherited by subsequent generations if they occur in germ cells.

The permanence of mutations is crucial because it distinguishes them from temporary changes, such as reversible alterations in RNA sequences. While environmental factors can contribute to mutations, the defining characteristic remains the change to the genetic sequence itself rather than the source of the change. Additionally, while mutations can occur in somatic cells, they are not limited to those; germline mutations play an equally important role in evolution and inheritance. Hence, the defining feature of a mutation is that it results in a lasting alteration to an organism's DNA.