What term describes a permanent change in a gene or chromosome?

A permanent change in a gene or chromosome is termed a mutation. Mutations can occur in several ways, such as through errors in DNA replication, exposure to certain chemicals, or radiation, and they can lead to changes in the traits of an organism. These changes may be beneficial, neutral, or harmful, depending on various factors, including how they affect the organism's ability to survive and reproduce.

Transcription refers to the process by which the information in a gene is transferred to messenger RNA, which is an essential step in the process of gene expression but does not involve a change to the DNA itself. Replication is the process of copying DNA to ensure that each new cell has the same genetic information, again not resulting in changes to the DNA structure. Transformation generally refers to the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material, often in the context of bacteria, and is not used to describe changes in a gene or chromosome itself.