Which of the following is an example of a polygenic trait?

• A. Sickle cell anemia
• B. Height in humans
• C. Blood type in humans
• D. Flower color in pea plants

Answer: (B)

Verified step by step guidance

1. Understand the definition of a polygenic trait: A polygenic trait is one that is controlled by two or more genes, often resulting in a continuous range of phenotypes.
2. Consider the examples given: Sickle cell anemia, height in humans, blood type in humans, and flower color in pea plants.
3. Analyze each example: Sickle cell anemia is caused by a mutation in a single gene, making it not polygenic. Blood type in humans is determined by a single gene with multiple alleles, so it is not polygenic. Flower color in pea plants is typically controlled by a single gene, according to Mendelian genetics.
4. Focus on height in humans: Height is influenced by multiple genes, each contributing a small amount to the overall phenotype, and is also affected by environmental factors, making it a classic example of a polygenic trait.
5. Conclude that height in humans is the correct example of a polygenic trait, as it involves the interaction of multiple genes to produce a range of phenotypes.