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2. Gary has 6 fingers on each hand & 6 toes on each foot. His wife Sandy and daughter Stephanie are normal. Extra digits is a dominant trait. What fraction of their children would be expected to have extra digits? My thougts: Let's say R= dominant allele, r= recessive allele. Since Gary has extra digits, I know his genotype is rr, but how do I do if the mother is RR or Rr?

3. Phenylketonuria (PKU) is a genetic defect harming the brain. A normal couple have a baby with PKU. What is the probability that their next child will be affected? What is the probability that if they have 2 more children, neither will be affected?