FAQ: I am writing to tell you that in the download section of Ornitho-Genetics VZW the last update of the Agapornis mutant gene list is dated 01/03/21 and I consider that it should be updated to be consistent with the type of inheritance described in the mutabase for example, I am referring to the specific case of the orange face mutation which in more recent publications is defined as “autosomal incomplete dominant”. In my humble opinion the most descriptive name for this mutation could be Factor Orange as I have already seen in some publications considering that it is already present in other species of psittaciformes in which its effect is visible not only in the mask.
Answer: You are right when you state that the name ‘orange face’ can be applied mainly to Agapornis roseicollis. Logic, it was in this species that the mutation was first described in the 1980s. In Agapornis roseicollis we get an orange mask colour, instead of the normal red mask that we have in the wild type.
And as you correctly stated, there are other species where we probably have this ‘orange face’ mutation and they don’t have an orange mask, but an orange chest etc… A more appropriate international name is therefore indeed needed, a name that can be used for all species. I agree completely that.
But the main question still is: what exactly does this mutation to the psittacofulvins in the feathers? With the information we have now, we SUSPECT that more yellow psittacofulvins are produced. In ‘orange face’ Agapornis roseicollis we have most probably the combination of red and yellow psittacofulvins and that can explain the orange colour.
But what about the species where the basic psittacofulvins present is not red, but for example already orange or yellow? We probably also have an ‘orange face’ mutation in Agapornis fischeri, but since the mask colour there is not red, but orange, we get now a yellow mask. The name ‘orange face’ or ‘factor orange’, will also cause confusion here.
So, I hope you understand my point of view, as I say that more time and research is needed to find a more appropriate name for this mutation. Just my thoughts!