If the population is in Hardy-Weinberg equilibrium what can we assume?

If the population is in Hardy-Weinberg equilibrium what can we assume?

• A. Gene frequencies will be constant and the genotypic frequencies will be constant
• B. Allele frequencies will vary generation to generation
• C. Genotypic frequencies are unpredictable
• D. Population size must be small

Answer: (C)

Hardy-Weinberg equilibrium means no evolution occurring, so allele frequencies stay the same from one generation to the next (assuming the usual conditions: large population, random mating, no mutation, no migration, no selection). With two alleles, if p is the frequency of one allele and q = 1 − p, the expected genotypes after mating are p^2 for the homozygous of that allele, 2pq for the heterozygotes, and q^2 for the other homozygote. This makes genotype frequencies fully predictable from the allele frequencies and they stay the same each generation as long as the equilibrium conditions hold. So the statement about genotypic frequencies being unpredictable is not correct. Under Hardy-Weinberg, allele frequencies do not vary generation to generation, and genotype frequencies follow the fixed proportions p^2 : 2pq : q^2. The idea that the population size must be small is also contrary to the assumptions, which require a large population to avoid drift.

Hardy-Weinberg equilibrium means no evolution occurring, so allele frequencies stay the same from one generation to the next (assuming the usual conditions: large population, random mating, no mutation, no migration, no selection). With two alleles, if p is the frequency of one allele and q = 1 − p, the expected genotypes after mating are p^2 for the homozygous of that allele, 2pq for the heterozygotes, and q^2 for the other homozygote. This makes genotype frequencies fully predictable from the allele frequencies and they stay the same each generation as long as the equilibrium conditions hold.

So the statement about genotypic frequencies being unpredictable is not correct. Under Hardy-Weinberg, allele frequencies do not vary generation to generation, and genotype frequencies follow the fixed proportions p^2 : 2pq : q^2. The idea that the population size must be small is also contrary to the assumptions, which require a large population to avoid drift.