A method for estimating the heritability of a phenotypic trait by comparing the concordance rates of identical and fraternal twins.

A method for estimating the heritability of a phenotypic trait by comparing the concordance rates of identical and fraternal twins.

• A. Twin method
• B. Heritability
• C. Genetic drift
• D. Stabilizing selection

Answer: (A)

Estimating how much genetics influences a trait by comparing how often identical twins share the trait versus fraternal twins captures the link between gene sameness and trait similarity. Identical twins share nearly all their genes, while fraternal twins share about half. If the trait is strongly genetic, identical twins will show higher concordance than fraternal twins; if the trait is mostly environmental, the concordance will be similar between the two types of twins. This difference allows a rough heritability estimate, often summarized as h^2 ≈ 2 × (r_MZ − r_DZ), under certain assumptions about the environment and gene–environment interactions. Remember that the method relies on comparable environments for both twin types and that real-world complexities can affect the estimate. Choices that describe broader concepts or other evolutionary processes don’t provide a method for estimating heritability from twin concordance.

Estimating how much genetics influences a trait by comparing how often identical twins share the trait versus fraternal twins captures the link between gene sameness and trait similarity. Identical twins share nearly all their genes, while fraternal twins share about half. If the trait is strongly genetic, identical twins will show higher concordance than fraternal twins; if the trait is mostly environmental, the concordance will be similar between the two types of twins. This difference allows a rough heritability estimate, often summarized as h^2 ≈ 2 × (r_MZ − r_DZ), under certain assumptions about the environment and gene–environment interactions. Remember that the method relies on comparable environments for both twin types and that real-world complexities can affect the estimate.

Choices that describe broader concepts or other evolutionary processes don’t provide a method for estimating heritability from twin concordance.