What is a key characteristic of quantitative traits?

Quantitative traits are characterized by the fact that they show continuous variation within a population. This means that rather than being categorized into distinct, separate groups, quantitative traits can take on a wide range of phenotypes. For example, traits such as height, weight, and milk production in animals are influenced by multiple genetic factors as well as environmental conditions, resulting in a bell-shaped distribution of traits across individuals.

This continuous variation is a hallmark of quantitative traits, as opposed to discrete traits, which typically exhibit clear-cut categories. In contrast, a trait influenced solely by a single gene would not exemplify the complexity typically associated with quantitative traits, and environmental factors alone do not account for the heritable nature of these traits. Therefore, the essence of quantitative traits lies in their ability to vary continuously, driven by the interplay of many genes and environmental influences.