I reckon it's on the cards that a single "white-fronted" mutation would occur. It would probably be a true blue as in Indian ringnecks and budgies. If such reappears it should be called blue if the back colour also shows the proper clear blue colour.Myzomela wrote:And just to confuse things I think originally there was also another white fronted blue scarlet which was a single mutation. I am not sure how it differed visually from the ones Tom is talking about (if at all) but I suspect they all got mixed up and the true recessive wfb scarlet was lost.
I believe the white-fronted is a combination of two separate mutations that decrease the psittacins in the bird's pigments. When combined, their effects compound so that you get a better "blue". A true blue mutation would eliminate all psittacins thus producing a clear blue and snow white pattern.