If a population is in Hardy-Weinberg equilibrium and if p and q are the frequencies of seperate alleles, then p² + 2pq + q² = 1 and p + q = 1, which implies that:

p² = frequency of homozygosity for allele pq² = frequency of homozygosity for allele q2pq = frequency of heterozygosity

The frequency of an X-linked recessive disease in males = q and in females q²

Hardy-Weinber assumptions include:- No mutation occurring at the locus- Natural seleciton is not occuring- Completely random mating- No net migration