Which statement best describes a trait with low heritability?

Which statement best describes a trait with low heritability?

• A. It responds extremely quickly to selection
• B. It responds moderately to selection
• C. It responds well to selection
• D. It is difficult to improve via selection

Answer: (D)

The idea being tested is how heritability influences how much a trait can respond to selection. When heritability is low, most of the observed variation in the trait comes from environmental factors rather than additive genetic differences. Because selection relies on phenotypic information to approximate genetic merit, a trait with low heritability provides a weak signal of genetic potential, so the expected response to selection is small. The basic relationship is that the response to selection equals the selection differential times heritability (R = h^2 × S); with a small h^2, the product is small, making genetic improvement through selection difficult. The statement that a trait is difficult to improve via selection best captures this idea. The other options imply stronger, quicker responses to selection, which would require higher heritability and are not consistent with low heritability.

The idea being tested is how heritability influences how much a trait can respond to selection. When heritability is low, most of the observed variation in the trait comes from environmental factors rather than additive genetic differences. Because selection relies on phenotypic information to approximate genetic merit, a trait with low heritability provides a weak signal of genetic potential, so the expected response to selection is small. The basic relationship is that the response to selection equals the selection differential times heritability (R = h^2 × S); with a small h^2, the product is small, making genetic improvement through selection difficult. The statement that a trait is difficult to improve via selection best captures this idea. The other options imply stronger, quicker responses to selection, which would require higher heritability and are not consistent with low heritability.