What is the probability that offspring ? is affected?

Question

Quizplus · Accepted Answer

If affected children always have an affected parent, then the trait is likely to be dominant. If a trait is dominant, then the genotype of an affected individual could be AA or Aa. An unaffected individual must be aa. If an affected individual has an unaffected parent, then the genotype of the affected child must be Aa. Individual III-2 has an unaffected parent so his genotype is Aa. Individual III-3 is unaffected, so her genotype is aa. The chance of ? being affected is the chance of them receiving the A allele from individual III-2, which is ½ (50%).

What Is the Probability That Offspring ? Is Affected