Under conditions of incomplete dominance, the F2 generation phenotypic distribution reveals_______________________?
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Answer: C. Phenotypic ratio corresponds to the genotypic ratio
Explanation
Incomplete dominance occurs when neither allele completely masks the other in heterozygous organisms. The resulting heterozygous offspring display an intermediate phenotype distinct from either homozygous parental type. Because every genotype produces a unique physical appearance, the phenotypic ratio matches the genotypic ratio. Mendelian inheritance typically shows complete dominance resulting in a standard three to one phenotypic ratio. Incomplete dominance demonstrates that gene expression can be quantitative rather than strictly binary in nature. Classic examples of incomplete dominance include flower color inheritance in snapdragons and four o clock plants.
Plant breeders observe intermediate phenotypes when developing ornamental flower varieties with novel color combinations. Geneticists use intermediate trait expression to calculate gene dosage effects in quantitative trait loci studies. Recognizing non-mendelian inheritance patterns prevents incorrect assumptions when analyzing complex breeding experiment data. A standard phenotypic ratio of three to one occurs exclusively under conditions of complete genetic dominance. A genotypic ratio of three to one is mathematically impossible for monohybrid crosses displaying standard segregation. Selecting none of the above is incorrect because the correct matching relationship is explicitly provided.
- Subject
- Agriculture
- Category
- Agriculture
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- —
- Difficulty
- medium
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