 Many non-primate placental mammals express multiple IFN-ω subtypes.This subtype of type I IFN was recently described as a pseudogene in human, but potentially functional in the domestic cat genome.In all other genomes of non-feline placental mammals, IFN-ν is a pseudogene; in some species, the pseudogene is well preserved, while in others, it is badly mutilated or is undetectable.