What are polygenic traits?

Options

A. traits controlled by a single gene
B. traits not controlled by any genes
C. traits controlled by two genes
D. traits controlled by three or more genes

Answer

**Step-by-Step Solution:**

1. **Definition of Polygenic Traits**: Polygenic traits are characteristics that are influenced by more than one gene. Unlike traits controlled by a single gene, polygenic traits result from the interaction of multiple genes.

2. **Phenotype and Morphology**: These traits can be observed in the phenotype, which refers to the observable physical characteristics or morphology of an organism. For example, traits such as height, skin color, and eye color are considered polygenic because they are determined by the cumulative effects of several genes.

3. **Example of Skin Color**: A classic example of a polygenic trait is human skin color. Skin color is influenced by multiple genes, often represented as dominant and recessive alleles. For instance, alleles A, B, and C can be dominant, while their lowercase counterparts (a, b, c) can be recessive. The combination of these alleles from both parents contributes to the individual's skin color.

4. **Genetic Combinations**: The various combinations of these alleles (e.g., AABBCC, AaBbCc, etc.) lead to a wide range of phenotypic expressions. This means that skin color can vary significantly among individuals due to the different combinations of these polygenic traits.

5. **Conclusion**: Therefore, polygenic traits are those traits that are controlled by multiple genes, and they contribute to the diversity of phenotypes observed in a population.

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