Multifactorial Traits Vs. Polygenic Traits, what is the difference? Multifactorial Traits-Trait that is controlled by many genes and is also influenced by the environment. Polygenic Traits- A trait that is determined by more than one pair of genes is called a polygenic trait. Examples include height and eye color. Polygenic traits are sometimes called continuous traits. Twins: Twin studies have been used to separate genetic and environmental contributions to a phenotype. A trait that occurs more frequently in both member of identical (MZ) twins than in both members of fraternal (DZ) twins probably has a significant genetic component. The concordance of a trait is the percentage of pairs in which both members express the trait. The study of monozygotic (MZ) twins separated at birth offers some unique insights into the nature vs. nurture debate. Examples of Multifactorial traits: Alcoholism- Signs and Symptoms of alcoholism include, Frequent intoxication, Heavy drinking patterns, Tendency to be in dangerous situations, and Black out drinking. Availability, Social Acceptance, and Advertising are the main environmental factors that play the biggest role in alcoholism. High Blood Pressure- Signs and Symptoms of high blood pressure include, Blood spots in eyes, Dizziness, Fatigue, and Facial Flushing. Stress and Obesity are the main environmental factors that play a huge role in high blood pressure. |
An Example of a Multifactorial is skin color.  MZ Twins- MZ twins are almost always more similar than DZ twins because of higher genetic similarity coupled with the same amount of environmental similarity. DZ Twins- twins share only about 50% of their polymorphisms. DZ twins tend to share many aspects of their environment (e.g., uterine environment, parenting style, education, wealth, culture, community) by virtue of being born in the same time and place.  |
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