Population Genetics The Hardy-Weinberg Law

The Hardy-Weinberg Law allows calculation of genotypes based on the allele frequencies in a population for a given genetic disorder. 

The following binomial expression governs the frequencies of the various genotypes in the population. 

the chances of occurrence of AA and aa homozygotes are p and ef, respectively, whereas the chances of finding an Aa heterozygote are 2pq. 

For example, in the United States, the incidence of live births of babies of Northern European descent who have cystic fibrosis (, for the aa genotype) can be estimated as approximately 1 in 2500 (0.04%). 

The Hardy-Weinberg Law can then be used to calculate the gene frequencies 

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