What is the term for a change in an organism's DNA sequence?

A change in an organism's DNA sequence is known as a mutation. Mutations can occur in various ways, such as through the substitution of one base for another, the insertion or deletion of bases, or larger structural changes like duplications or inversions of DNA segments. These alterations can have a range of effects on the organism, from benign to significant changes in traits or functions.

In contrast to mutation, transcription refers to the process where the DNA sequence of a gene is copied into messenger RNA (mRNA). This is a critical step in gene expression but does not involve a change in the original DNA sequence. Replication is the process by which DNA makes a copy of itself before cell division, ensuring that both daughter cells have an identical set of DNA. Translocation, on the other hand, typically refers to a specific type of mutation where a segment of DNA is moved from one location to another, which again is a form of mutation but does not encompass the entire scope of what a mutation can be. Therefore, the term that best describes any change in an organism's DNA sequence is mutation.