Dr John Pilkington answers questions on Genetics

Question to Dr John Pilkington from Dusty Powter

Question: I recently paired an opaline laurel dominant pied cock to an opaline spangle dominant pied violet hen (with a view to producing dark factored birds in various varieties). Four chicks were produced, opal dominant pied laurel, opal. dominant pied cobalt, opaline spangle dominant pied violet and opaline spangle dom.pied grey. With regards the last chick, it has obvious patches of violet on its chest and is quite dark for a grey but is not plum coloured. What would you expect is its true colour ? Could it be a mauve or is it simply just a grey shade impacted by the violet factor? Or could it be some other possibility I have not considered.

Answer from John Pilkington:
Questions relating to the identification of budgerigars, without my having sight of the birds in question are always difficult to answer, because I must rely on the description supplied to me. Therefore, my answers in such cases are based purely upon genetic theory, using the processes of elimination and deduction.

Firstly, I am assuming that you are identifying the Laurel as a single factor Dark Green (the UK term). Basically, you have paired a Dark Green cock to a Cobalt Violet (visual violet) hen and produced a Dark Green, a Cobalt, a Cobalt Violet (visual violet) and a Grey, and you are questioning if you have correctly identified this last Grey (?) bird.

Since Grey is dominant, one of the parents must be a visual Grey in order for an offspring to be a visual Grey. In view of the fact that you have described the cock as "Laurel" rather than Dark Green, there is a possibility in my opinion, that you may have mistaken a Grey Green, and this could account for the appearance of a Grey offspring from the pairing you have described.

There are, of course, other visual grey coloured phenotypes caused by recessive genes: namely a recessive Grey and Slate. It would be possible for both the cock and hen in your pairing to be heterozygous for such factors, thus producing a grey coloured offspring.

If we discount the idea that neither parent possesses any of the grey-producing genes, then we must assume that the Grey(?) offspring is not grey-coloured, but is in fact a Mauve. Since both parents possess a single Dark gene, there is a 25% chance of producing double factor Dark offspring. Without having sight of this bird, I would suggest that in all probability this bird is a Mauve. In order to confirm the identity, test mate this bird to a Skyblue: if it is Mauve, all its offspring will be Cobalt, and since it shows violet patches on the body, 50% of its offspring should be visual Violet.

Editors' note: I regret that Dr Pilkington is unable to answer any further questions.

Other pages in this section

Designed and created by Arcadia WebSite Design.