A few weeks ago, I was approached by Florian Gouze (France) who had reservations by the* AR grey* Agapornis roseicollis, a mutation that has been introduced a few years ago in South-America. He found that there was a color difference between heterozygous and homozygous birds. If the mutation is indeed autosomal recessive, there is in theory no visual difference between a normal green and a split green. That would indicate that this ‘greymutation’ inherits incomplete dominant.
The same observations have been made recently by Harry Bens, an aviculturist in the Netherlands.
Last year we examined and compared feathers of *grey* Agapornis roseicollis with the autosomal recessive grey Forpus coelestis by cross-section but these didn’t gave enough concrete info, so I guess we will have other technology to examine these feathers. One thing is sure, it is a completely different mutation than slate, dominant grey, misty and slaty.
So a few weeks ago, I contacted Alessandro D’Angieri, a Brazilian judge, who was the one who discovered this mutation. He admitted that the inheritance is not autosomal recessive. He told me that the single factor bird (heterozygote) is slightly violet (purple) shaded, but it is required very good eyes to see it, mainly in inner wing coverts. At first sight, it would be similar to light SF violet with no dark factor. That is why very few people can see it. DF birds, (homozygote) will produce the visual grey. He referred to the Orange face factor, heterozygotes to OF can be distinguished by trained eyes so indeed also OF is intermediate dominant. That is why, a first moment the original breeder set them as “recessive” due to the difficult identification of heterozygote phenotype. But Alessandro also realize if that if everyone can see SF and DF it is quite acceptable just take out the word recessive and suggested to name it “Grey factor”.” G factor” with (intermediate) incomplete dominance inheritance. We also believe that the name “Grey factor” fits in perfectly with that phenotype.
So we have the dominant grey (complete dominant, no visual differences between SF and DF) in budgies, the AR grey (autosomal recessive grey) in Forpus coelestis and the incomplete dominant greyfactor in Agapornis roseicollis.
- Dominant grey (complete dominant)
- AR grey (autosomal recessive)
- SF and DF grey factor (incomplete dominant)
Three different mutations and three different names that all refer to the greyish phenotype of these mutations.