Evolution of hes gene family in vertebrates: the hes5 cluster genes have specifically increased in frogs.
Aya KuretaniTakayoshi YamamotoMasanori TairaTatsuo MichiuePublished in: BMC ecology and evolution (2021)
These data suggest that the hes5 cluster existed in the gnathostome ancestor but became a single gene in mammals. The number of hes5 cluster genes were specifically large in frogs.