1. Two strains of E. coli, A and B, are inoculated into a chemostat in equal proportions. After one generation, the frequency of strain B is 20%. Calculate the fitness of strain B relative to strain A.

2. Hurler syndrome is an autosomal recessive disease caused by a deficiency of the enzyme alpha?L?iduronidase. Affected individuals are mentally retarded, and they have skeletal abnormalities and short stature. The population incidence is about 1 in 90,000.

a. Compute the allelic and genotypic frequencies for the disease assuming Hardy?Weinberg equilibrium. Show your work and express your answer to three significant figures.

b. What would be the increased risk of Hurler syndrome among the offspring of first?cousin matings? Show your work and express your final answer to three significant figures.