genetic resources for (budgerigar) breeders
Example 5: the cin gene
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The gene itself was introduced before, so we start off with some pairings:
Pairing 5.1: cinnamon cock x normal hen
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What happens with the inverse pairing?
Pairing 5.2: normal cock x cinnamon hen
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From these two last pairings, we can see that we no longer can interchange cock and hen in a pairing.
Another thing you might have notice: the cock determines the colour of the young hens. A young hen receives the "empty" Y-chromosome from the mother and so the X-chromosome from the father determines solely the phenotype.
The other way around, we can tell the genotype of the cock from his daughters: cinnamon hens have a cinnamon or split cinnamon father, normal hens have a normal or split cinnamon father. A normal cock/cinnamon can indeed produce both normal and cinnamon hens, since it has both alleles of the gene:
Pairing 5.4: normal cock/cinnamon x cinnamon hen
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Apart from the trivial pairings (normal cock x normal hen = normal offspring & cinnamon cock x cinnamon hen = cinnamon offspring) there's only one pairing left:
Pairing 5.5: normal cock/cinnamon x normal hen
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You cannot see a difference between the normal cocks and the split cocks. Further breeding with these cocks is the only way to distinguish between them. This is the reason why some people dislike pairing 5.5: they cannot predict the genotype of some of the offspring. I personally don't mind, but when your trying to keep clear of cinnamons, for instance when you're breeding greywings, a cock from such a pairing may bring in cinnamon.
The op gene: opaline
It inherits in just the same way as cinnamon: just replace all the cin's with op's and 'cinnamon' with 'opaline' in the previous pairings (even a simple text processor can do it for you). But, keeping in mind recombination, we know that genes on the same chromosome are linked and therefore with these two genes (cin and op) we also have to concider recombination. The recombination frequency is very high, about 30% (Warner & Taylor, mentioned by MUTAVI).
When you've fully understood recombination and example 5, you should be able to calculate all possible parings with opaline and cinnamon. Nevertheless, I will give a few pairings as example.
Example 6 The cin and the op gene combined
Pairing 6.1: cinnamon cock x opaline hen
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