CramX Logo

Q
QuestionBiology

What is the difference between complete dominance, codominance, and incomplete dominance?
12 months agoReport content

Answer

Full Solution Locked

Sign in to view the complete step-by-step solution and unlock all study resources.

Step 1:
I'll explain the differences between complete dominance, codominance, and incomplete dominance in genetics:

Step 2:
: Complete Dominance

- A person with $$Bb$$ genotype will have brown eyes because the brown allele completely dominates the blue allele
- In complete dominance, one allele completely masks the expression of the other allele - The dominant allele is fully expressed in the phenotype - The recessive allele is completely hidden when paired with a dominant allele Example:

Step 3:
: Codominance

- The blood type shows both $$A$$ and $$B$$ antigens simultaneously
- In codominance, both alleles are expressed equally in the phenotype - Neither allele is recessive or dominant - Both alleles contribute to the observable trait - Represented as both alleles being fully expressed Example:

Step 4:
: Incomplete Dominance

- In snapdragon flowers, red ($$RR$$) and white ($$WW$$) alleles result in pink ($$RW$$) when combined
- In incomplete dominance, neither allele is completely dominant - The resulting phenotype is a blend or intermediate of the two alleles - The heterozygous organism shows a phenotype that is a mixture of both alleles - Represented by an intermediate expression Example: - The pink color is a true blend, not just a masked expression of one allele

Final Answer

- Complete Dominance: One allele completely masks the other - Codominance: Both alleles are fully and equally expressed - Incomplete Dominance: Alleles blend to create an intermediate phenotype