Match each human phenotypic trait on the left with its corresponding pattern of variation and underlying genetic mechanism on the right.
- ABO blood group systemDiscontinuous variation controlled by multiple alleles at a single locus, yielding distinct non-overlapping phenotypes.
- Adult body heightContinuous variation governed by polygenes, producing a broad, uninterrupted spectrum of phenotypic measurements.
- Rhesus factor statusDiscontinuous variation determined by monogenic inheritance, presenting clear-cut presence or absence phenotypes.
- Skin pigmentation gradientContinuous variation mediated by polygenic additive inheritance and significantly modulated by environmental exposure.
Answer
The correct pairings match ABO blood group system with discontinuous variation controlled by multiple alleles; Adult body height with continuous variation governed by polygenes; Rhesus factor status with discontinuous variation determined by monogenic inheritance; and Skin pigmentation gradient with continuous variation mediated by polygenes and environmental exposure.
Each phenotypic trait is correctly matched according to whether its phenotypic distribution is continuous (quantitative spectrum driven by polygenes) or discontinuous (qualitative discrete classes driven by single-gene or multiple-allele systems). ABO blood grouping involves multiple alleles yielding distinct blood groups; height is a classic polygenic quantitative continuous trait; Rhesus factor is a simple monogenic positive/negative discontinuous trait; and skin color is a polygenic continuous trait influenced by environmental factors.
Step-by-Step Solution
Key Concept
Continuous and Discontinuous Variation