Determinant of Offspring Genotypic Frequency
Genotypic frequency of offspring will depend upon-
- Gene frequencies of parents — Correct Answer
- Genotypic frequencies of parents
- Both Gene and Genotypic frequencies of parents
- None of the above
Explanation:
Correct Answer: Gene Frequencies of Parents
According to Hardy-Weinberg Law, the genotypic frequencies of offspring depend only upon the gene (allele) frequencies of the parents — not on the parental genotypic frequencies directly.
Hardy-Weinberg Law — Key Points
- Statement: In a large, random-mating population, in the absence of mutation, migration, and selection, gene and genotypic frequencies remain constant from generation to generation
- H-W Equation: p² + 2pq + q² = 1 (where p + q = 1)
- Genotypic frequency of offspring: P = p²; H = 2pq; Q = q²
- Key note: Genotypic frequency of offspring depends only upon gene frequencies of parents
H-W Equilibrium — Gene & Genotype Relationships
| Genotype | Frequency | Formula |
|---|---|---|
| AA (Dominant homozygote) | P | p² |
| Aa (Heterozygote) | H | 2pq |
| aa (Recessive homozygote) | Q | q² |
Forces Affecting H-W Equilibrium
- Systemic forces: Mutation, Migration, Selection (affect large and small populations)
- Dispersive forces: Random genetic drift / Sewell Wright effect (only small populations)
Why Other Options Are Wrong
- Genotypic frequencies of parents → once random mating occurs, what matters is the pool of alleles (gene frequencies), not the specific genotypic combinations
- Both → redundant; genotypic frequencies are derived from gene frequencies, so gene frequencies alone suffice
- None of the above → incorrect; gene frequencies of parents are the direct determinant
