In genetics, what does concordance rate measure?

In genetics, what does concordance rate measure?

• A. Agreement proportion of a trait between twin individuals
• B. Extent two individuals share identical environments
• C. Percentage of genes shared by siblings
• D. Rate of trait development in adulthood

Answer: (A)

Concordance rate is about how often twins share the same trait. It’s the proportion of twin pairs in which both people either show the trait or both don’t, usually expressed as a percentage. This is most informative in twin studies because monozygotic twins share nearly all their genes while dizygotic twins share about half; a higher concordance in monozygotic pairs points to genetic influence on the trait. For example, if a large portion of monozygotic twins are concordant for a condition but dizygotic twins are less concordant, that suggests genetics play a role. It doesn’t measure how similar environments are, nor does it indicate the exact percent of genes siblings share, nor the rate at which a trait develops in adulthood.

Concordance rate is about how often twins share the same trait. It’s the proportion of twin pairs in which both people either show the trait or both don’t, usually expressed as a percentage. This is most informative in twin studies because monozygotic twins share nearly all their genes while dizygotic twins share about half; a higher concordance in monozygotic pairs points to genetic influence on the trait. For example, if a large portion of monozygotic twins are concordant for a condition but dizygotic twins are less concordant, that suggests genetics play a role. It doesn’t measure how similar environments are, nor does it indicate the exact percent of genes siblings share, nor the rate at which a trait develops in adulthood.