Which type of trait is not expressed in the phenotype?

Recessive traits are characterized by their lack of expression in the phenotype unless two copies of the recessive allele are present. In other words, recessive traits can be masked by dominant traits; therefore, if an individual possesses a dominant allele, the characteristic associated with the recessive allele will not be expressed. For example, if a dominant allele for a certain trait (like flower color) is present along with a recessive allele, the dominant trait will be the one observed in the physical characteristics of the organism.

In situations where an organism has two recessive alleles, the recessive trait will manifest in the phenotype. However, because it can also remain unexpressed in the presence of a dominant trait, it is correct to say that recessive traits are not always reflected in the phenotype.

In contrast, dominant traits will always be visible when at least one dominant allele is present. Epistatic traits involve interactions between genes where one gene can mask the expression of another, and polygenic traits are influenced by multiple genes and typically show a range of phenotypic expressions. Recessive traits, however, are uniquely defined by their occasional inconspicuousness in the phenotype when paired with dominant alleles.