Posts by Loic-Leducq
Why are the mutations in zebrafinch of pale back, masked (new type) and masked old type combined with each other so difficult to predict !?
Quite simply because we cannot speak at the genetic level of different mutations but rather of allelic versions of a single gene. The pale back, the masked and the old type mask are due to the same gene but which has three allelic versions.
To understand well let's make the parallel with man, the color of the eyes for example, whatever our eye color, our iris color and coded by the same gene, but this gene has many different versions (alleles) which allow us to have the color panel that we know.
Now that we know a little more about what complicates these crosses, let's take a look at how each allele behaves in relation to each other.
Everything is a story of dominance and co-dominance or recessivity.
A small table to illustrate all this :
Allele / allele Pale back Masqued Masqued OT Pale back x Pale back Pale back Masqued Pale back x Masqued Masqued OT Pale back Masqued x
*OT = Old type
In this double entry table you can see that it allele dominates the other, the bird will therefore have the phenotype of the allele which dominates, be careful, it is not because the allele is dominated that it does not not influence. See pale back / OT mask, the back is more diluted because of the masked OT allele.
From this result we can draw the first conclusions :
- The pale back can be masked or OT masked.
- The masked can be a masked OT split but cannot be a pale back wearer (pb dominates masked = pb / masked). *pb = pale back
- The masked OT cannot carry a pale back, nor a masked person because the latter two dominate him.
The first zebrafinch presented at the exhibition were far from those we now have in our farms. They were rather filiform and small in all respects resembling the majority of the birds that we currently find at the pet store on the corner.
The evolution does not know made in a day but it has been relatively fast. Here we will talk about the grey zebrafinch, all simply because it is my specialty, and I am starting to know it well.
We can observe that the greys, which are a classic (We call «classic» the greys and the basic mutations that are the brown, pale back and masked.), presented in the major exhibitions is no longer very far from the perfect grey. The type and size are for the most part excellent level and the difference is mainly on the color.
To locate each descriptive terms used in the rest of the article, you can use this diagram: Descriptive terms in zebrafinch.
1. The main defects of grey males
In recent years many defects have appeared in the gray we have the leisure to see in our exhibitions. I’m going to introduce a few of them that I think are most commonly encountered on display or on our farms.
a) The stripes behind the cheeks
For the last couple of years, at least from what I’ve personally noticed, we’ve been seeing signs of zebra around the cheek. This defect is rather noticeable in black cheek greys, but rather recent in grey males. It is still time to eradicate it from gray strains before it is fully generalized to grey zebrafinch.
Because of the similarity to the defect in black cheeks, I do not think it can be equated with a black cheek factor. Indeed, this defect appears even in strains having no affiliation with a strain of black cheeks.
On the other hand, we can think that this phenomenon is due to a high concentration of eumelanin (black), which is sought in gray for a dark back and in black cheeks for an intense black color.
b) Tear spreading in the cheeks
Another defect is the tear, which gives an impression of diffusion in the cheek by the presence of some black feathers in them, and of a line under the eye. Usually in my breeding these are birds that have deep chestnut cheeks. I think we still have it, we can equate it to an excess of eumelanin in this area.