Biology: Concepts and Investigations 2nd Edition by Mariëlle Hoefnagels

Exercise 25

Holstein cattle suffer from the condition citrullinemia, in which homozygous recessive calves die within a week of birth because they cannot break down ammonia that is produced when amino acids are metabolized. If a cow that is heterozygous for the citrullinemia gene is inseminated by a bull that is homozygous dominant, what is the probability that a calf inherits citrullinemia?