Which inheritance pattern involves multiple genes and produces continuous variation?

Which inheritance pattern involves multiple genes and produces continuous variation?

• A. Epistatic inheritance
• B. Monogenic inheritance
• C. Polygenic inheritance
• D. Pleiotropic inheritance

Answer: (C)

Polygenic inheritance is when many genes, each contributing a small effect, influence a single trait. Because these effects add up, you get a continuous range of phenotypes rather than distinct categories. Environmental factors can also shape the outcome, widening the variation. Height or skin color in humans are classic examples. In contrast, traits controlled by a single gene (monogenic) tend to show discrete categories, one gene interactions between loci (epistasis) modifies how genes express but doesn’t inherently create a smooth spectrum, and pleiotropy involves one gene affecting many different traits rather than producing continuous variation.

Polygenic inheritance is when many genes, each contributing a small effect, influence a single trait. Because these effects add up, you get a continuous range of phenotypes rather than distinct categories. Environmental factors can also shape the outcome, widening the variation. Height or skin color in humans are classic examples. In contrast, traits controlled by a single gene (monogenic) tend to show discrete categories, one gene interactions between loci (epistasis) modifies how genes express but doesn’t inherently create a smooth spectrum, and pleiotropy involves one gene affecting many different traits rather than producing continuous variation.