Which term describes the variability in phenotype expression among individuals with the same genotype?

The term that accurately describes the variability in phenotype expression among individuals who share the same genotype is expressivity. Expressivity refers to the degree or range of phenotypic expression that a particular genotype can produce in different individuals. This concept highlights that even though individuals may have identical genetic makeups, the way their genetic traits are manifested as observable characteristics can differ greatly.

For instance, in the case of a genetic disorder that requires a specific allele for its expression, some individuals may show severe symptoms, while others might exhibit only mild symptoms or none at all. This variation can be influenced by various factors, including environmental influences, other interacting genes, or even different life experiences.

In contrast, penetrance refers to the proportion of individuals with a specific genotype who actually express the expected phenotype at all, while hemizygosity refers to the state of having only one copy of a gene in an otherwise diploid organism, which does not relate to variability in phenotype among genotypes. Quantitative variation describes traits that vary continuously and do not fit neatly into simple categories, rather than focusing on the variability of expression of the same trait across individuals with the same genotype.