Answer the following in regard to multifactorial traits in human twins. If the trait is substantially influenced by genes, would you expect the concordance rate to be higher in MZ twins or higher in DZ twins? Explain your reasoning.

Key Concepts

Concordance Rate

Concordance rate refers to the likelihood that both twins in a pair exhibit the same trait or condition. In genetic studies, this measure helps determine the influence of genetics versus environment on traits. A higher concordance rate in monozygotic (MZ) twins compared to dizygotic (DZ) twins suggests a stronger genetic component, as MZ twins share 100% of their genes, while DZ twins share about 50%.

Monozygotic (MZ) vs. Dizygotic (DZ) Twins

Monozygotic twins, or identical twins, originate from a single fertilized egg that splits into two embryos, resulting in genetically identical individuals. In contrast, dizygotic twins, or fraternal twins, develop from two separate eggs fertilized by two different sperm cells, sharing approximately 50% of their genetic material. This distinction is crucial for understanding the genetic basis of traits, as MZ twins provide insights into the heritability of traits.

Multifactorial Traits

Multifactorial traits are characteristics influenced by multiple genes and environmental factors, making their inheritance complex. Examples include height, intelligence, and susceptibility to diseases. In the context of twins, examining concordance rates for multifactorial traits helps researchers understand the relative contributions of genetic predisposition and environmental influences, providing insights into how these traits are expressed in individuals.