We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is a Quantitative Trait?

By Kenneth W. Michael Wills
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

In genetics, a quantitative trait is one that varies in its characteristics and expressions. Two or more genes, along with environmental interactions, are usually responsible for the ultimate expression. Such traits are described in numbers and may vary in degrees. Most quantitative traits are continuous and often do not fall into any discrete categories. The study of the inheritance of such traits is called “Quantitative Genetics,” and such phenotypes in humans include — but are not limited to — height, intelligence quotient (IQ) and blood pressure.

When scientists know a genotype or the internal genetic code for a specific trait, they can predict the resulting phenotypes or outward characteristics of that trait. These are referred to as discontinuous traits and are assigned discrete classes. Not all traits, however, fall neatly into a discrete classification, but instead are continuous and hard to predict. Such types of traits are called quantitative traits, because they are usually recorded as number distributions.

Polygenic inheritance is the term used by scientists to describe the formation of a quantitative trait. Genes that influence the value of quantitative traits are referred to as quantitative trait locus (QTL). The formation of quantitative traits involves two or more genes contributing to a phenotypic characteristic and, often, also involves interaction with the environment. Height in humans, for example, involves a number of genes; however, the ultimate expression of the gene is impacted by environmental factors, such as available nutrition. Rather than following a specific pattern, the traits vary along a continuous gradient that is often illustrated on a bell curve.

Numbers and percentages are the primary methods of documenting quantitative traits. Numerical values of quantitative traits are often ordered from the highest to lowest and depict a continuous order rather that a specified count along a continuous gradient. Values of quantitative traits often differ only in small, arbitrary amounts rather than by fixed amounts. Therefore, most scientists assume continuous data rather than specific values or counts when documenting quantitative traits. Scientists attempt to predict the variance of a quantitative trait to find the mean of distribution and depict the spread on a bell curve.

Expressions of quantitative traits appear in just about every organism, often notably in plant and animal life. In plants, examples include crop yield, color distribution and disease resistance. With animals and people weight, height, learning ability and even blood pressure are each expressed as a quantitative trait.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources
Discussion Comments
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.