Genetics Chapter 7 Multifactorial Traits Quiz

Study Notes

Polygenic and Multifactorial Traits

Polygenic traits arise from multiple genes influencing a single trait, each providing small additive effects.
Examples include body shape, height, skin color, and hair type.
Multifactorial traits result from interactions between genes and environmental factors.

Mendelian Ratios and Environmental Influences

Multifactorial traits do not adhere to Mendelian inheritance patterns.
Environmental influences encompass all factors outside of DNA that can impact traits.
Pure polygenic traits are rare and typically influenced by environmental factors.

Continuum of Traits

Polygenic traits display a continuous variation, often represented by a bell-shaped curve.
Variability arises from different combinations of alleles and environmental factors, creating a spectrum of phenotypes.
Common examples of traits with continuous variation include height and eye color.

Mendelian Genetics Context

Individual genes follow Mendelian genetics, with dominant and recessive patterns dictating inheritance.
However, when considering multiple genes together in polygenic traits, Mendelian ratios are not produced.

Fingerprint Patterns

Fingerprints are a multifactorial trait influenced by parental alleles and environmental conditions during gestation.
Unique fingerprint patterns arise due to varying heat and pressure in the womb, making them distinct for each individual.
The types of fingerprints include arches, loops, and whorls, with whorls exhibiting two tri-radii.

Genetic Influence and Environmental Factors

Differences in gestational environment contribute to dermatoglyphic variations in identical twins.
Fingerprints are uniquely formed in the womb, ensuring all individuals possess distinct patterns.

Human Height and Environmental Impact

Height exhibits a continuous distribution influenced by genetics and environmental factors such as diet and health.
Historical context shows that environmental conditions, like those experienced by Jews during the Holocaust, impacted expressed genetic potential for height.

Eye Color Genetics

Eye color is minimally influenced by environmental factors, modeled by two genes with two alleles that interact additively.
The five primary human eye colors are blue, grey, green, hazel, and brown.

Skin Color and Environmental Interaction

Skin color is a polygenic trait, primarily determined by the amount of melanin produced; more melanin leads to darker skin.
Sun exposure acts as an environmental factor, affecting skin color through tanning.

Genetic Heritage

Allele frequencies serve as the best indicator of shared heritage within populations, reflecting genetic commonality and relatedness.

Description

Test your knowledge on multifactorial traits and polygenic traits with this chapter-based quiz. Understand the role of multiple genes and environmental interactions in determining these traits. Explore key definitions and concepts to enhance your grasp of genetics.