Genetics of CinnamonSummary:
Cinnamon - sex-linked recessive
Normal - dominant
Cinnamon is a sex-linked mutation. This means that the gene is located on the x-chromosome. Male budgies have two x-chromosomes (XX) and female budgies have an x-chromosome and a y-chromosome (XY). Since the gene is recessive to normal, male budgies must have two cinnamon genes (one on each x-chromosome) to be a cinnamon variety. However, since female budgies have only one x-chromosome, if their x-chromosome has the cinnamon gene, they will be the cinnamon variety. It is because females need only one gene to express the trait that sex-linked mutations such as cinnamon are more common in female budgies. Here, we will represent the cinnamon gene on the x-chromosome as "Xc" and the x-chromosome with the normal gene as "X". There are three genotype possibilities for a male budgie:
And there are two genotype possibilities for a female budgie:
Below are some punnet square examples of pairings. As you will see, if your goal is to breed a sex-linked mutation like cinnamon, besides breeding two visually cinnamon budgies, the best results will be from the pairing of a male who is split for cinnamon to a cinnamon female.
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A normal male budgie and a cinnamon female budgie
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A cinnamon male budgie and a normal female budgie
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A male split for cinnamon budgie and a normal female
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A male split for cinnamon and a female cinnamon budgie
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