Dominance describes how the two alleles at a locus are jointly translated into an observable phenotype, and it is only distinguishable in the heterozygous genotype — homozygotes express their single allele type regardless of the dominance pattern. Three patterns are defined: complete dominance, in which only the dominant allele is expressed and the recessive allele is masked so that two different genotypes yield the same phenotype; codominance, in which both alleles are fully and separately expressed so that the distinct traits of each appear simultaneously in the phenotype; and incomplete dominance, in which neither allele is fully dominant and the phenotype is an intermediate blend of the two. The concept belongs to Mendelian and classical genetics, refining the genotype–phenotype mapping beyond the simple dominant/recessive dichotomy.
Dominance describes how the two alleles at a locus are jointly translated into an observable phenotype, and it is only distinguishable in the heterozygous genotype — homozygotes express their single …