Nonrecessive

Nonrecessive is a term used in genetics to describe an allele that expresses its trait even when only one copy is present in the genotype. This is in contrast to a recessive allele, which only expresses its trait when two copies are present. When considering a gene with two alleles, one nonrecessive and one recessive, the genotype of an individual will determine the phenotype.

If an individual has two copies of the nonrecessive allele (homozygous nonrecessive), the trait associated with that allele will be observed. If an individual has one copy of the nonrecessive allele and one copy of the recessive allele (heterozygous), the trait of the nonrecessive allele will still be expressed. This is because the nonrecessive allele masks the effect of the recessive allele. The only way for the recessive trait to be observed is if the individual inherits two copies of the recessive allele (homozygous recessive).

In simpler terms, a nonrecessive allele is dominant. The term "nonrecessive" emphasizes that the allele is not recessive, rather than stating it is dominant. This distinction is often made to avoid potential confusion with complete dominance, as some nonrecessive alleles exhibit incomplete dominance or codominance, where both alleles contribute to the phenotype in a heterozygous individual. However, in the context of a simple dominant/recessive relationship, nonrecessive is synonymous with dominant.