Fursus makatmus is a autosomal dominant disease homozygous l

Fursus makatmus is a autosomal dominant disease, homozygous lethal, seen at a frequency of 1 in 10,000 individuals. Individuals with this disease have an unquenchable desire to swim in freezing cold water. Assume the locus is in Hardy Weinberg Equilibrium.

A man affected with Fursus makatmus and an unaffected woman have a newborn son. What is the probability that the son has Fursus makatmus? Assume mating is at random.

A. 0.5

B. 0.75

C. 0

D. 0.25

E. 1E-05

Solution

A. 0.5

in this question, the frequency, Hardy-Weinberg equilibrium and symptoms are not required to solve.

since, it is given the man is affected with Fursus makatmus. therefore the genotype would be either \'Aa\' or \'AA\'. but in the question, it is given homozygouslethal. therefore, the genotype would be \'Aa\'. the gametes would be \'A\' and \'a\'.

the woman is unaffected. the genotype would be \'aa\'. only one gamete would be formed, i.e, \'a\'

the offspring may be either \'Aa\' or \'aa\'.

since only \'Aa\' causes the disease, the probability is 0.5