4.1. Extra copies of fish Cry
The extra Cry homologs in teleosts were likely generated by ancient
polyploidy events and recent family- and/or species-specific genome
duplication (Zardoya and Doadrio, 1999; Dehal and Boore, 2005; Liu
et al., 2015). In the evolution history of vertebrates, their genomes duplicated
twice (2R) (Taylor et al., 2003; Hoegg et al., 2004; Meyer and
Van de Peer, 2005). The third genome duplication, which is named
the fish-specific genome duplication (FSGD) and occurred in the basal