Gene Inheritance explanation
Recessive Gene Explanation
Recessive genes require one copy of the gene to be passed down from each parent to the offspring so the offspring has two copies. A bird with only one copy is “split” to that mutation, and will pass down that gene to 50% of his or her offspring but will not appear to have the gene. A bird with two copies of the recessive genes show the color and are called “visual” for that gene. Recessive genes are inherited the same way regardless of the sex of the bird.
Recessive genes include but are not limited to
Blue (“turquoise” in Green Cheeked Conures, and “white face” in cockatiels)
Pied (some species also have a dominant pied version in which case this gene would be called “recessive pied”
Sex-Linked Gene Explanation
Sex linked genes are inherited differently than recessive genes.
Male birds require two copies of a sex-linked gene to be “visual,” that is to show the mutation in their coloring. The male bird must receive one copy of the gene from each of his parents. A male bird who receives only one copy of the gene will be “split” to the gene, that is they will carry the gene but not show it, and will pass it on to 50% of their offspring. A visual male will pass on the gene to 100% of his offspring. Male birds pass on one copy of their sex-linked genes to both their male and female offspring.
Female birds require only one copy of a sex-linked gene to visually show the mutation in their coloring. Because they require only one copy to be visual, female birds cannot be “split” to a sex-linked mutation. Female birds pass their sex-linked genes to ONLY their male offspring.
Because of the unique way sex-linked genes are inherited they provide a convenient way to sex offspring in some cases. If the mother bird does not carry the gene then no visual males can be produced. This means any visual offspring produced by a pair where the hen does not carry the gene is a female, and has received the gene from the father. If neither parent is visual and you get visual offspring then you know the offspring are female, that they received the gene from their father, and thus you know the father is split to that sex-linked gene.
Sex-Linked Genes include but are not limited to
Opaline (called “pearl” in Cockatiels and “yellow-sided in Green Cheeked Conures)