From the Research
The answer is D. Incomplete dominance, as it is the inheritance pattern that best explains the observation of pink-flowering plant offspring from a cross between red-flowering and white-flowering plants, due to the partial expression of both alleles in heterozygous individuals, as supported by the study on the molecular basis of incomplete dominance at the A locus of CHS-D in the common morning glory, Ipomoea purpurea 1.
Key Points
- In incomplete dominance, neither allele is completely dominant over the other, resulting in a blended phenotype in heterozygous individuals.
- The pink color represents a partial expression of both the red and white alleles, demonstrating the classic example of incomplete dominance in flower color inheritance.
- This differs from codominance, where both alleles would be fully expressed simultaneously (not creating a blend), and from epistasis, which involves interaction between different genes.
- It's also not inbreeding, which refers to mating between closely related individuals, or polygenic inheritance, which involves multiple genes controlling a single trait.
Supporting Evidence
- A study on the molecular basis of incomplete dominance at the A locus of CHS-D in the common morning glory, Ipomoea purpurea, found that the mutable a(flaked (a(f)) allele confers incomplete dominance in flower pigmentation 1.
- Another study on incomplete dominance of deleterious alleles in maize found that incorporating information about putatively deleterious alleles can inform genomic selection models and improve phenotypic prediction 2.
- A review on mechanisms of Mendelian dominance discussed the role of incomplete dominance in genetic dominance, highlighting its importance in understanding the relationships between genotypic and phenotypic values 3.