Answer to Question #141099 in Psychology for LEBRON

Question

Often the concordance rate in twin studies is less than 100%, even in MZ twins. Why might this be true?

Answer 1

Concordance Rate in Twins

Generally, concordance in genetic study refers to the presence of the same trait in members of pair twins. Identical twins share their DNA because they were formed from the same sperm and ovum of their parents. A higher discordant rate than concordant indicates the influence of the environment on twin traits. A higher concordance rate often expresses evident genetic components in monozygotic twins than dizygotic twins. Theoretically, the samples from the identical twins show 100%, but due to assaying errors and somatic mutation, they are usually less than 100% (Castelbaum et al. 2019). Thus, the percentage range between 99% to 99.95%.

References

Castelbaum, L., Sylvester, C. M., Zhang, Y., Yu, Q., & Constantino, J. N. (2019). On the nature of monozygotic twin concordance and discordance for autistic trait severity: a quantitative analysis. Behavior genetics, 1-10. file:///C:/Users/user/Downloads/Castelbaum2020_Article_OnTheNatureOfMonozygoticTwinCo%20(1).pd