Molecular phylogeny of the GchI feedback regulatory protein in vertebrates. Maximum-likelihood phylogeny of Gchfr protein sequences based on 95 AA positions. The tree is rooted with Gchfr from nematode. Numbers at the branches denote bootstrap values (maximum likelihood/neighbor joining) above 50%. Gchfr is duplicated in salmon and rainbow trout due to the salmonid-specific tetraploidization.