Which term describes a trait controlled by two or more genes that results in a wide range of phenotypes?

Which term describes a trait controlled by two or more genes that results in a wide range of phenotypes?

• A. Chromatin
• B. Pedigree chart
• C. Sex-linked traits
• D. Polygenic traits

Answer: (D)

Polygenic traits arise when many genes contribute to a single characteristic, producing a broad spectrum of phenotypes. Each gene adds a small effect, and the combined influence across numerous genes creates continuous variation rather than distinct categories. This is why traits like height, skin color, and eye color can vary smoothly across a population. Environment can also tweak the final expression, adding additional variation. The other terms describe different concepts—chromatin is about DNA packaging, a pedigree chart is a family tree used to study inheritance, and sex-linked traits involve genes on sex chromosomes—none of which capture the idea of multiple genes shaping a trait to produce a wide range of phenotypes.

Polygenic traits arise when many genes contribute to a single characteristic, producing a broad spectrum of phenotypes. Each gene adds a small effect, and the combined influence across numerous genes creates continuous variation rather than distinct categories. This is why traits like height, skin color, and eye color can vary smoothly across a population. Environment can also tweak the final expression, adding additional variation. The other terms describe different concepts—chromatin is about DNA packaging, a pedigree chart is a family tree used to study inheritance, and sex-linked traits involve genes on sex chromosomes—none of which capture the idea of multiple genes shaping a trait to produce a wide range of phenotypes.