Why do polygenic characterist ics have many phenotypes? |...

Name: Problem 3, Chapter 24: Genetics: A Conceptual Approach
Uploaded: 2021-08-09T15:45:25-08:00
Duration: 1 min 59 s
Channel: Mathew Botros
Description: Why do polygenic characterist ics have many phenotypes?

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Key Concepts

Quantitative Traits

Quantitative traits are characteristics that are measured on a continuous scale, such as height or skin color, and are typically influenced by multiple genes as well as environmental factors. The polygenic control of these traits leads to a continuous distribution of phenotypes, explaining why there are many gradations rather than just a few distinct forms.

Phenotypic Variation

Phenotypic variation in polygenic traits is high because the many genes involved can recombine in numerous ways during reproduction. This genetic diversity results in a continuum of trait values rather than discrete categories, providing a rich array of observable outcomes.

Polygenic Inheritance

Polygenic inheritance refers to the phenomenon where a single trait is controlled by multiple genes rather than a single gene. This results in a cumulative effect where each gene contributes a small part to the final phenotype, making the trait's determination more complex and less predictable on a simple dominant-recessive basis.

Additive Genetic Effects

In polygenic traits, the effects of individual genes add together to influence the overall phenotype. This additive nature means that even small variations at each gene can sum to create a broad spectrum of expression, which is why you observe a wide range of phenotypes.

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