Problem
• Step I: Pick a letter to represent the alleles.
• Step II: Determine the genotypes of the parents involved.
• Step III: Determine the possible genotypes of the affected individuals.
• Step IV: Use a Punnett Square to show the possible genotypes of the offspring.
• Step V: Answer any questions.
A. A mating of 2 cats occurs. One of the parents has long-hair, which is a recessive allele. The litter of kittens has 3 short-haired and 2 long-haired kittens. What does the second parent look like, and what is its genotype? (HINT: You need to put the kittens in the Punnet Square and work backwards).
B. In humans, tongue rolling is a dominant trait, those with the recessive condition cannot roll their tongues. Two parents who can roll their tongues have a child who cannot. What is the probability of having another child who cannot roll their tongue?
C. Ms. Green is a 31-year-old woman who has type O blood. She has children with Mr. Gray who has type AB blood. They have two children, the first with type A blood, the second with type O. Mr. Gray suspects that one of the children is not his biological offspring. Which child may not be his? Use a Punnett Square to explain your answer.
D. Mr. Sutton and Ms. Smith have different hair texture. Mr. Sutton has straight hair and Ms. Smith has very curly hair. Hair texture is determined by genes that are incompletely dominant. What are the possible hair textures of their kids?
E. Ms. Washington and Mr. Carver do not understand why all of their sons are color blind (an X-linked trait) but none of their daughters are. Neither parent is color blind. How would you explain this to the parents?