Question: Cystic fibrosis is a recessive genetic mutation that causes
severe health problems in humans and …
Cystic fibrosis is a recessive genetic mutation that causes
severe health problems in humans and leads to death before
reproduction. As a lethal allele the theory of natural selection
would predict that this allele should be eliminated from the
population, yet the occurrence of cf in North America is about 1 in
a) Calculate the genotypic frequency of individuals in this
population afflicted with cf.
b) Calculate the frequency of the cf allele (q) in the
population and the corresponding frequency of the normal allele
c) What is the expected genotypic frequency of carriers of the
cf allele in this population?
d) What are the odds that a given individual is a carrier of the
e) If selection acts to remove less fit alleles from the
population then the ultimate equilibrium frequency of the cf allele
should be 0. How can this allele have such a high prevalence in the
North American population?