In an isolated of 90 desert bighorn sheep, a mutant recessive allele c when homozygous causes curled coats in both males and females. The normal dominant allele C produces straight coats. A biologist studying these sheep counts four with curled coats. She also takes blood samples from the population for DNA analysis, which reveals that 19 of the sheep are heterozygous carriers of the c allele. To increase genetic diversity in this bighorn sheep population, fifteen sheep are introduced from a population where the c allele is absent.
Using Mendelian genetics, what is the expected frequency of straight coats and curled coats? What is the inbreeding coefficient (F) for this population?