Population Genetics MCAT Practice Question

A 35-year-old woman with a family history of cystic fibrosis (CF) is counseled regarding carrier risk. CF is an autosomal recessive disorder caused by mutations in the CFTR gene. In the general population, the frequency of the normal allele (F) is 0.9 and the frequency of the disease allele (f) is 0.1. However, in a isolated community with a history of consanguinity, a screening program reveals that 64% of individuals with genotype ff (homozygous for the disease allele) die before reproductive age from severe pulmonary complications, while all other genotypes survive to reproduce. Assuming Hardy-Weinberg equilibrium conditions apply among survivors and random mating occurs, what is the expected frequency of the disease allele (f) in the next generation of this isolated community?