Failure of one of a pair of genes ( allele s) present in an individual to express itself in an observable manner because of the greater influence, or dominance , of its opposite-acting partner.
Both alleles affect the same inherited characteristic, but the presence of the recessive gene cannot be determined by observation of the organism; that is, though present in the organism's genotype (gene makeup), the recessive trait is not evident in its phenotype (observable characteristics). The term recessive is applied both to the trait in the organism having the alleles of a gene pair in the recessive condition and to the allele whose effect can be masked by another allele of the same gene.