Gene frequency calculation in genetics uses the Hardy-Weinberg equilibrium principle. For a gene with two alleles A and a, the allele frequencies p and q must sum to 1, and genotype frequencies follow the equation p squared plus 2pq plus q squared equals 1. This forms the foundation for calculating disease frequencies in populations.
To calculate allele frequency from disease rate, we use the Hardy-Weinberg principle. Given that the disease frequency is 0.6 percent, and assuming this is a recessive disorder, the frequency of the aa genotype equals 0.006. Therefore, q squared equals 0.006, so q equals the square root of 0.006, which is approximately 0.0775. The dominant allele frequency p equals 1 minus q, which is approximately 0.9225.