Some disorders represent a non–X-linked trait that is recessive. Inheritance of Single-Gene Problems

Some disorders represent a non–X-linked trait that is recessive. Inheritance of Single-Gene Problems

A person usually must receive two abnormal genes, one from each parent to have the disorder. Neither parent has the disorder but each has a 50% chance of passing the abnormal gene to the children if both parents carry one abnormal gene and one normal gene. Consequently, each young son or daughter has

A 25% possibility of inheriting two irregular genes (and therefore of developing the condition)

A 25% possibility of inheriting two normal genes

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