Question

Two completely normal parents have a child with a recessive autosomal disorder. How does this happen, and what are the chances?

Answer 1

well for this to happen, both parents much represent at least one of the recessive allels, because if one parent did and the other didn't then there is no way that the child would have this disorder. Let me show you what I mean.



The only way for a recessive disorder to be present in the child is the parents must both have a recessive allele for that gene and they most both contribute the recessive allele to b "pp"


so the chances are 1/4 = 25% of the child getting this disorder.

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