Isogene

Isogene is a term used in genetics and biology to describe a line or organism whose genome is identical or nearly identical to a reference genotype. It is closely related to the concept of isogenic lines, and in some usages isogene is used interchangeably with isogenic, though some authors reserve it for a line that is genetically identical except for a defined region or a single locus.

Isogenen lines are typically produced to minimize genetic background variation in experimental materials. Methods include backcrossing a donor strain to a reference parent for multiple generations while selecting for the desired locus, or applying modern genome-editing techniques (such as CRISPR) to insert or modify a specific allele within a uniform genetic background. Once established, isogenes or isogenic lines are propagated to maintain the shared genotype.

Applications span plant and animal genetics, cell biology, and biomedical research. In plants, near-isogenic lines are used to map quantitative traits and study gene function with controlled backgrounds. In cell biology and medicine, isogenic cell lines or organisms enable researchers to isolate the effects of a single gene or mutation by removing background genetic variability, improving reproducibility and interpretability of results.

Limitations include residual genetic or epigenetic differences that can arise during propagation and cell culture, as well as genetic drift over passages. Epigenetic state and environmental history can influence phenotypes even in highly similar genotypes.

See also: isogenic, backcross, genome editing, CRISPR, near-isogenic line.