Will some birds gain UV vision through gene mutation soon?
To your first question: yes, you understood that correctly. A lot of major changes occur with a single mutation in one coding sequence of DNA. To your second: the developent of UV vision is dependant on a lot of things. The way I understand it, the main function of UV vision in birds is courtship – male birds with bright plumage often have feathers coloured with uv sensitive pigments, that reflect the uv light rather than absorbing it like regular feathers; the females can see this uv light and the brighter its reflected the more handsom the male appears. However, its not well understood whether UV vision or the pigment evolved first – my guess would be the UV vision evolved first, and pigment after, which would certainly be condusive to other bird species evolving UV vision. However, since most bird species without UV vision do not have the special UV pigments, there would be no reproductive benefit to having UV vision and the mutation would be unlikely to become fixed in the species
