Which term describes a form of a gene that is expressed in the phenotype, regardless of whether it is homozygous or heterozygous?

The term that describes a form of a gene expressed in the phenotype, regardless of whether it is present in two identical alleles (homozygous) or one each of two different alleles (heterozygous), is dominant. Dominant alleles will always manifest their traits in the organism’s appearance, overshadowing the effects of other alleles when paired with them.

For instance, if an organism has one dominant allele and one recessive allele for a trait, the dominant allele will determine the phenotype, leading to the expression of its associated characteristic. This is why dominant alleles are significant in genetics; they can dictate the physical traits that are observed.

In contrast, recessive alleles only express their traits when an individual has two copies of that allele. Codominant alleles exhibit both traits equally when present together, while incomplete dominance results in a blended phenotype that is different from either parent trait. Understanding these concepts is crucial for grasping basic genetic principles in biology.