1. Phenylketonuria (PKU) is an inherited disorder in which amutation in a single autosomal gene leads to inability to breakdown the amino acid called phenylalanine. Babies born with PKUoften have the following symptoms: a musty odor to the skin, hair,and urine; vomiting and diarrhea; irritability; itchy skin, andsensitivity to light. If this condition goes untreated, it can leadto the loss of skills, growth and developmental delays andseizures. The term that best fits with this description of PKUis:
| | epistasis |
| | pleiotropy |
| | incomplete dominance |
| | polygenic inheritance |
2.
PKU is inherited as an autosomal recessive disorder. Bob and Janare healthy. Bob is not a carrier of this disorder, but Jan is acarrier of the PKU allele (She is heterozygous.). If they have achild, what is the probability that this child will show thedisorder PKU (have the phenotype for PKU)?
3.
PKU is inherited as an autosomal recessive disorder. Bob and Janare healthy. Bob is not a carrier of this disorder, but Jan is acarrier of the PKU allele (She is heterozygous.). If they have achild, what is the probability that this child will show thedisorder PKU (have the phenotype for PKU)?
4. Huntington disease is inherited as an autosomal dominantdisorder with adult onset. Sally has Huntingon disease (She is aheterozygote for this gene). Her partner John does not haveHuntington. Suppose Sally and John have 3 children. What is theprobability that NONE of their children inherit HuntingtonDisease?
