Diagram illustrating the gene duplication events for the α1gene in zebrafish. (A) A tandem duplication generated twoα1 paralogs as follows: α1A, shown in gray andα1B, hashed. (B) The tandem is duplicated by the large scale duplication in the bony fish lineage α1A andα1B. (C) Present-day zebrafish. One duplicate pair is found on LG 1, where the α1A paralog has undergone two further gene duplications to generate three genes (α1A1,α1A2a, and α1A2b). We do not have evidence for the existence of the other α1A paralog. It may have been lost or remained as a pseudogene and is indicated by a question mark. The α1B paralogs have give rise to the α1B1 gene on LG 1 and α1B2 on LG 9. The arrangement of the genes on the chromosome is arbitrary.
