Which trait is described as an autosomal dominant trait with widespread lactose tolerance in some populations?

Which trait is described as an autosomal dominant trait with widespread lactose tolerance in some populations?

• A. Qualitative variation
• B. Polygenic traits
• C. Pleiotropy
• D. Lactose tolerance

Answer: (D)

Lactase persistence, the ability to digest lactose into adulthood, is typically inherited as an autosomal dominant trait—one copy of the persistence allele is enough to maintain lactase production. In populations with a long history of dairy farming, this allele spread because dairy-consuming individuals had a nutritional advantage, leading to widespread lactose tolerance in those groups. The question is pointing to the trait itself and its inheritance pattern, not to a broader genetic category. The other terms describe different genetic concepts: qualitative variation refers to discrete phenotypes without specifying inheritance; polygenic traits involve many genes contributing to a trait; pleiotropy means one gene affects multiple traits. So lactose tolerance best fits the description.

Lactase persistence, the ability to digest lactose into adulthood, is typically inherited as an autosomal dominant trait—one copy of the persistence allele is enough to maintain lactase production. In populations with a long history of dairy farming, this allele spread because dairy-consuming individuals had a nutritional advantage, leading to widespread lactose tolerance in those groups. The question is pointing to the trait itself and its inheritance pattern, not to a broader genetic category. The other terms describe different genetic concepts: qualitative variation refers to discrete phenotypes without specifying inheritance; polygenic traits involve many genes contributing to a trait; pleiotropy means one gene affects multiple traits. So lactose tolerance best fits the description.