Two different alleles of a gene expressed in a heterozygous individual describe which concept?

Two different alleles of a gene expressed in a heterozygous individual describe which concept?

• A. Dominant
• B. Co-dominant
• C. Blending inheritance
• D. Particulate inheritance

Answer: (B)

Co-dominance means both alleles are expressed in a heterozygous individual, so you see traits from both alleles at the same time. This is why someone with one copy of each allele can display both products rather than just one. A classic example is the ABO blood group system, where an individual with one A and one B allele has red blood cells carrying both A and B antigens, yielding blood type AB. This differs from complete dominance, where the dominant allele masks the other in the heterozygote, so only one phenotype appears. It also differs from blending inheritance, which would produce a single intermediate phenotype rather than two distinct traits expressed together. Particulate inheritance underlies these patterns, with alleles existing as discrete units that can be expressed in combination, as seen in co-dominance.

Co-dominance means both alleles are expressed in a heterozygous individual, so you see traits from both alleles at the same time. This is why someone with one copy of each allele can display both products rather than just one. A classic example is the ABO blood group system, where an individual with one A and one B allele has red blood cells carrying both A and B antigens, yielding blood type AB. This differs from complete dominance, where the dominant allele masks the other in the heterozygote, so only one phenotype appears. It also differs from blending inheritance, which would produce a single intermediate phenotype rather than two distinct traits expressed together. Particulate inheritance underlies these patterns, with alleles existing as discrete units that can be expressed in combination, as seen in co-dominance.