Agapornis roseicollis pale?
By Dirk Van den Abeele
Ornitho-Genetics VZW
MUTAVI, Research & Advice Group
Published BVA Magazine August 2017
About three years ago I was approached by the Greek aviculturist and judge, Panagiotis Vrannas regarding an Agapornis roseicollis with a deviating colour. According to him the description matched the description of a possible *pastel* Agapornis roseicollis as mentioned in the Dutch edition of my book. [1, p. 178]. And this was indeed correct, when I compared the bird’s phenotype with this description there were a lot of similarities, except for the description of the outer flight feathers. These deviated. The description of these outer flight feathers in *pastel* Agapornis roseicollis mentions that, and I quote:
“All wing feathers (large, middle and small) are light grey with a predominantly yellow outer vane which has a light cream coloured edge. With the exception of the outer large wing feathers whose outer vane is so narrow that there is hardly any yellow visible’, all outer flight feathers clearly have an edge.
Panagiotis was given the same advice as others to set up trial pairings, because the first requirement for a mutation is of course that the phenotype inherits. I did leave the possibility of a *pastel* open but everything was filed neatly, as always, in a separate file in the folder ‘to be checked’.
Last year I went to the UK together with Panagiotis and Edwin Vloebergen. I gave a lecture on mutations in Forpus and Edwin and Panagiotis judged. Of course this ‘strange’ bird was mentioned again. Panagiotis told me that the father of these birds was an SL ino green and the mother an opaline aqua. The birds had their first young with this deviating colour in 2014 but unfortunately the young died after a few months. Early 2016 he again had 2 young from that pair, one of which had this deviating colour. According to Panagiotis it was more than likely a male. When I asked him whether an SL ino green (lutino) young was born from this pair he answered negatively.
This rang a bell. It is not the first time in aviculture that a bird split for SL ino or even homozygotic SL ino, suddenly produces an entirely different mutant. For instance the opaline Agapornis roseicollis. The first opaline was born from a pair where the male was split SL ino [1, p. 148], [2, p. 331]
Genetically this is entirely possible. I do not want to complicate matters too much, but this could have various causes. For instance, it could be that a translocation occurred whereby one part of a gene has been moved or disappeared. Then there is also the possibility that a, new, separate gene, be it on the Z chromosome or not, has an epistatic effect on the expression of these genes [3]–[5].
But I asked Panagiotis to check whether this bird was definitely ‘not’ a female, just to be certain. I already suspected at that time that we might be dealing with pale. Pale is an SL recessive mutation which has only recently been noticed in Agapornis fischeri [1, p. 379], [2, p. 419] and probably surfaced for the first time about 15 years ago in the Lineolated Parakeet [Bolborhynchus lineola]. This mutation has a limited eumelanin reduction (+/- 15%) and what is important: trial pairings with the Catharina Parakeet have shown that this mutation is clearly an allele of SL ino. In my opinion this fits better because the clear edging on the outer flight feathers reminded me of this. Panagiotis had the DNA of the young tested and my suspicion was confirmed: the young with this deviating colour was indeed a female.
This female was paired with a green male and recently they had their first three young: 2 females and 1 male, all, as expected, green. If my suspicion is correct and this is the pale mutation, then the young male must be split pale and can combined with a green female to produce pale females.
Then Panagiotis took it a step further and paired the pale female with a green SL ino male. If my reasoning is correct that this pale is an allele of the SL ino gene, we would be able to breed PaleIno males from this. In the first nest there was indeed a male with a deviating colour. I quote Panagiotis “He has light grey feet and nails and 30%-35% reduction of eumelanin in the body, also the typical characteristic primary feathers of pale.”
Because all of this I do think that we can now speak of pale in Agapornis roseicollis.
Thanks to Panagiotis!!!
Dirk
Literature:
[1] D. Van den Abeele, Agaporniden, handboek en naslaggids – deel 2, 2013de ed., vol. 2, 2 vols. Over dieren, 2013.
[2] D. Van den Abeele, Lovebirds Compendium, 1ste ed. Warffum- The Netherlands: About Pets, 2016.
[3] E. T. Domyan e.a., “Epistatic and Combinatorial Effects of Pigmentary Gene Mutations in the Domestic Pigeon”, Curr. Biol., vol. 24, nr. 4, pp. 459–464, Feb. 2014.
[4] H. J. Cordell, “Epistasis: what it means, what it doesn’t mean, and statistical methods to detect it in humans”, Hum. Mol. Genet., vol. 11, nr. 20, pp. 2463–2468, Jan. 2002.
[5] J. H. Moore, “A global view of epistasis”, Nat. Genet., vol. 37, nr. 1, pp. 13–14, Jan. 2005.
