Incomplete Dominance vs Codominance: Key Differences Explained
Incomplete dominance is when one allele doesn’t fully mask another, creating an intermediate phenotype like pink flowers from red and white parents. Codominance lets both alleles show fully at once, so red and white patches appear together.
People confuse them because both involve two alleles mixing, but one blends while the other displays both traits side-by-side. Students often think “blend” equals “both show,” leading to mix-ups in homework and exams.
Key Differences
Incomplete dominance yields a blended trait; codominance displays both traits distinctly. Genotypically, they both carry two different alleles, yet phenotypically one merges while the other separates—pink vs roan cattle patches.
Examples and Daily Life
See pink snapdragons for incomplete dominance and roan cattle or AB blood type for codominance. Spot these in gardens, farms, or blood banks to remember: pink blend vs. visible red-and-white.
Which one creates a brand-new color?
Incomplete dominance, like the pink flower from red and white parents.
Is AB blood incomplete dominance or codominance?
Codominance—both A and B antigens are fully expressed.