Read How Genotype Frequencies Change
Read changing genotype frequencies by first identifying the changed process, then recalculating from the new allele frequencies or mating system.
Genotype Frequencies and Inbreeding is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Reset Hardy–Weinberg after selection
Selection can change allele frequencies. Once random mating resumes, calculate zygotes from the new p and q values. With p(A)=0.8 and q(a)=0.2, AA=p²=0.64, Aa=2pq=0.32 and aa=q²=0.04. Choose B.
Rank inbreeding by homozygosity
More closely related matings expose identical alleles more quickly. Self-fertilisation drives homozygosity up fastest, brother–sister mating is next, and first-cousin mating is slowest. Match the steepness of the curves before naming the breeding system: choose C.
OlympIQ exam lens
- ✓After allele frequencies change, use the new p and q values.
- ✓Random mating produces p², 2pq and q² zygote frequencies.
- ✓Selfing raises homozygosity faster than sib or cousin mating.
Do not keep old genotype frequencies after the stem explicitly changes allele frequency.
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