FIG. 1.

Chromosomal context of a nested gene. (A) Diagram of an intronic nested gene. The nested gene is represented by a red arrow, while the external host gene is represented by a yellow arrow interrupted by an intron. (B) Diagram of a nonintronic nested gene. The nested gene and host gene are indicated as above. This review focuses on these two types of nested genes; it does not consider protein pairs that arise by alternative splicing or gene pairs that share a transcriptional start site or termination sequence.