Types of Genetic Traits

Genetic traits follow different inheritance patterns depending on how many copies of a gene you have and how they work together. Understanding these patterns helps explain why some traits appear in certain family members and others don't.

Dominant Traits

Sometimes, having a single copy of a gene results in a disease or trait. We call this a dominant genetic model. For example, someone with a single risk allele for Huntington's disease will develop the condition.

Recessive Traits

Some diseases or traits only occur if you have two copies of a gene. We call this a recessive genetic model. Sickle cell anemia is one example.

Additive Traits

Most traits don't follow simple dominant or recessive patterns. Instead, the majority of traits are the result of multiple genes working together in an additive manner.

Human height follows an additive model. For each gene that influences height, two copies of the "tall" allele add twice as much total height as having only one copy. Because many genes influence height, most alleles and variants work this way.