Starch grain synthesis in pea seeds is an example of

Options

A. codominance
B. incomplete dominance
C. multiple allele
D. complete dominance

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about starch grain synthesis in pea seeds and what genetic principle it exemplifies.

2. **Identifying Alleles**: Let's denote the alleles involved in starch grain size. We can use:
- Capital B (B) for the allele that produces larger starch grains.
- Small b (b) for the allele that produces smaller starch grains.

3. **Crossing Pure Breeds**: We consider a cross between two purebred pea plants:
- One plant with genotype BB (large grain size).
- Another plant with genotype bb (small grain size).

4. **Gametic Fusion**: When these two plants are crossed, the gametes will fuse to produce offspring with the genotype Bb.

5. **Analyzing the Offspring Phenotype**: Since B is dominant over b, we would expect the offspring to exhibit the phenotype of the dominant allele (larger grains). However, in this case, the offspring exhibit an intermediate phenotype, which is neither large nor small.

6. **Defining Incomplete Dominance**: The observation that the offspring have an intermediate grain size indicates that the expression of the alleles is not complete. This phenomenon, where the dominant allele does not completely mask the effect of the recessive allele, is known as incomplete dominance.

7. **Conclusion**: Therefore, starch grain synthesis in pea seeds is an example of incomplete dominance.

**Final Answer**: Incomplete dominance.

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