Enter your Parent 1 and Parent 2 alleles into the Codominance Calculator, add an optional Trait Name, and toggle Show Genotypic Ratios or Show Phenotype Analysis to reveal the Most Common Phenotype, Total Genotype Combinations, Heterozygous Offspring count, and which traits show Codominant Expression across the genetic cross.
Most Common Phenotype
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Total Genotype Combinations
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Heterozygous Offspring
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Codominant Expression
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Codominance occurs when both alleles in a heterozygote are fully expressed simultaneously, without blending. A classic example is ABO blood types, where IA and IB alleles are codominant, resulting in AB blood type.
In codominance, both traits are fully expressed together (like AB blood type), while in incomplete dominance, the traits blend to create an intermediate phenotype (like pink flowers from red and white parents).
Yes, this calculator works for any codominant traits including human examples like ABO blood types, HLA antigens, and certain protein variants. Just enter the appropriate allele symbols.
Genotype ratios show the probability of each genetic combination occurring in offspring. For example, a 1:2:1 ratio means 25% chance of each homozygote and 50% chance of the heterozygote.
In codominance, heterozygotes express both parental traits simultaneously. The calculator shows which offspring will display single traits versus combined codominant expression.
Use standard genetic notation like IA, IB for blood types, or any letter/symbol system. The calculator treats different symbols as different alleles and analyzes their inheritance patterns.
This calculator works with any pair of alleles for each parent. For traits with more than two allele variants in a population, run separate calculations for different parental combinations.