Search Magazine December 01, 2008

A Minute to Understanding: phenotype

What is a phenotype?

Phenotype is a word one hears a lot at The Jackson Laboratory. A mutation in an important gene will usually change the phenotype of an organism. Of particular interest is what's known as a disease phenotype. But while phenotype is an important term, its full meaning is hard to pin down.

A phenotype includes traits visible to the eye, such as height, eye and hair color, and so on. It also includes less obvious traits, such as metabolic rate and organ function.

Phenotypes reflect a combination of genes and environment. It's important to note that the same genes in a different environment can produce different phenotypes. For example, a mouse (or a person!) fed a high-fat diet will weigh more and have more fat tissue than a mouse with the same genetics fed a restricted calorie diet. Therefore, phenotype is a key component of disease research. In fact, the Mouse Phenome Project at the Laboratory has data for about 1,000 characteristics relevant to a great variety of human diseases.