High School

If the genotype frequencies start at 30% AA, 20% AB, and 50% BB, what are the expected genotype frequencies after one generation of random mating?

Answer :

Final answer:

When calculating the expected genotype frequencies after one random mating generation starting with 30% AA, 20% AB, and 50% BB, using the Hardy-Weinberg principle, the expected frequencies are 16% AA, 48% AB, and 36% BB.

Explanation:

Expected Genotype Frequencies After Random Mating

When considering genotype frequencies after one generation of random mating starting with 30% AA, 20% AB, and 50% BB, it is important to use the Hardy-Weinberg principle to predict the outcome. To do this, we need to calculate the allele frequencies. Let 'A' and 'B' be the two alleles for a gene. The frequency of allele 'A' (p) is calculated by adding the frequency of the homozygous genotype (AA) to half the frequency of the heterozygous genotype (AB), which is (0.3 + 0.1 = 0.4). Similarly, the frequency of allele 'B' (q) is calculated as (0.5 + 0.1 = 0.6). According to the Hardy-Weinberg equilibrium, the frequencies after random mating would be p^2 for AA, 2pq for AB, and q^2 for BB. Therefore, the expected frequencies would be:

AB: 2pq = 2*(0.4)*(0.6) = 0.48 or 48%

BB: q^2 = (0.6)^2 = 0.36 or 36%

The expected genotype frequencies after one generation of random mating would be 16% AA, 48% AB, and 36% BB, if there were no other evolutionary forces at play.