Hardy-Weinberg model

When the allele frequencies in a population remain constant from generation to generation, the population is said to be in Hardy-Weinberg equilibrium where there is no evolution. Such conditions are when there is a very large population size, no migration, no net mutations, random mating, and no natural selection. In a very large population, genetic drift, which is the change in a population's allele frequencies due to chance, can cause genotype frequencies to change over …

…sum to 100% (p+q=1) and that all individuals sum to 100% (p2+2pq+q2=1) Below is the work shown to calculate the frequencies of a rabbit population that consists of 100,000 rabbits of which 25,000 are white and 75,000 are agouti. If 25,000 rabbits are white then 25,000/100,000=q2 So 0.25=q2 Route 0.25=q 0.5=q Since p+q=1 Then 1-q=p So 1-0.5=0.5 Thus p=0.5 And p2=(0.5)(0.5)=0.25 Now we know 2(0.5)(0.5)=2pq p2=homozygous dominant frequency=0.25 q2=recessive allele frequency=0.25 2pq=heterozygous frequency=0.5