mendelian genetics

Question

A monohybrid cross between two heterozygotes yields what phenotypic ratio (complete dominance)?

RankGuru · Accepted Answer

1. **Definition**: A monohybrid cross studies the inheritance of a single pair of contrasting characters.
2. **The Cross**: Parents are $Aa 	imes Aa$.
3. **Genotypic Result**: Using a Punnett square, we get: 
   - $1 \ AA$ (Homozygous dominant)
   - $2 \ Aa$ (Heterozygous)
   - $1 \ aa$ (Homozygous recessive)
   - Genotypic Ratio = **$1 : 2 : 1$**.
4. **Phenotypic Result**: Under complete dominance, both $AA$ and $Aa$ express the dominant trait, while only $aa$ expresses the recessive trait.
   - Dominant phenotype : Recessive phenotype = $(1+2) : 1 = \mathbf{3 : 1}$.

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mendelian genetics

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