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The Sex Linked Mutations - and how it works
Sex-linked: For a female to be produced the male parent must be at least split for the mutation. For a male to be produced the male parent must be at least split for the mutation and the female parent must visually show the mutation. Females cannot be split for sex-linked mutations, only the males. You have no way of knowing what mutations, if any, a male may be split to unless you know what mutations the birds parents were, or by test breeding.
Sex-Linked mutations : Pearl, Cinnamon, Lutino, and Yellow-faced
Basic Genetic Results
Sex-linked: For a female to be produced the male parent must be at least split for the mutation. For a male to be produced the male parent must be at least split for the mutation and the female parent must visually show the mutation. Females cannot be split for sex-linked mutations, only the males. You have no way of knowing what mutations, if any, a male may be split to unless you know what mutations the birds parents were, or by test breeding.
Sex-Linked mutations : Pearl, Cinnamon, Lutino, and Yellow-faced
Basic Genetic Results
Normal Male x Normal Female = 100% Normal Offspring
Sex-Linked Male x Sex-Linked Female = 100% Sex-Linked Offspring (meaning you will get both Males & Females who are visually the sex linked mutation)
Sex-Linked Male x Normal Female = 50% Normal Males that are Split to the Mutation, 50% Sex-Linked Females.
Sex-Linked Female x Normal Male = 50% Normal Males that are Split to the Mutation, 50% Normal Females.
Recessive x Recessive (Sex Doesn't Matter) = 100% Recessive Offspring
Recessive x Normal = 100% Split to the Mutation Offspring
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Sex-Linked Male x Sex-Linked Female = 100% Sex-Linked Offspring (meaning you will get both Males & Females who are visually the sex linked mutation)
Sex-Linked Male x Normal Female = 50% Normal Males that are Split to the Mutation, 50% Sex-Linked Females.
Sex-Linked Female x Normal Male = 50% Normal Males that are Split to the Mutation, 50% Normal Females.
Recessive x Recessive (Sex Doesn't Matter) = 100% Recessive Offspring
Recessive x Normal = 100% Split to the Mutation Offspring
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- Males have two "X" chromosomes; females have only one. The genes causing the color mutations Cinnamon, Lutino, Pearl, and Yellow-Cheek, are always found on the X chromosome, NEVER on the Y. Because there is no color gene present on the Y chromosome which might mask the sex linked color, female cockatiels will always VISUALLY show Cinnamon, Lutino, Pearl and/or Yellow-Cheek if it is present on their X chromosome. A female, therefore, can never be SPLIT to Cinnamon, Lutino, Pearl or Yellow-Cheek. A good rule to remember here is "what you see is what you get"!Males, however, may carry one or more of the sex linked genes on only ONE of their two X chromosomes. If they do, the DOMINANT NORMAL will mask that trait, and the male will be considered SPLIT to that mutation. For example, if a male carries Pearl on only one of his X chromosomes, which would be genetically coded X XP, he is split to pearl. If he carries Cinnamon on the other X chromosome (XC XP), he would be split to Cinnamon AND Pearl since he only has one gene for each color. If, however, he had Cinnamon and Pearl on the SAME X chromosome (XCP X) he would be split to cinnamon-pearl. NOTE: It makes no difference whether the sex linked gene is carried on the first X chromosome or the second in the genetic code.
A male cockatiel will always donate one of his two X chromosomes to the offspring, but a female can donate either her X or her Y. If the mother passes along her one X chromosome, the offspring is MALE (X X). If she gives her Y chromosome instead, the result is a FEMALE (X Y). In sex linked mutations, it is good to remember that males will always throw daughters of the same mutation, and mothers will always have sons that are at least split to any mutation they carry.