Lecture 14: Quant Genetics

What is a quantitative trait?

How do you calculate the variance?

How is the standard deviation calculated? What is its relationship to the variance?

How can Mendelian genetics be reconciled with continuous variation in quantitative traits?

What are the two main components of phenotypic variation?

How might environmental variation influence phenotypic variation? How might this cause traits influenced by only a few genes to normally (bell-curved) phenotypic distributions?

What are the components of genotypic variation?

What is broad sense heritability? How is it calculated?

What are the components of broad sense heritability?

What is additive genetic variance

What is dominance genetic variance?

What is the interaction or epistatic genetic variance?

What is narrow sense heritability, and how is it calculated?

How do you estimate narrow sense heritability if you know the phenotypes of parents and offspring?

What is the range of values for h²? What does it mean if h² is 0, 1, or 0.63?

Why is narrow sense heritability so important? What component of phenotypic variation is exposed to selection and will respond to selection?

What is directional selection? What was the example used in class?

What is stabilizing selection? What is another term for stabilizing selection?

What was the example of balancing selection I used in class?

What is disruptive selection? What was the example?

In plant and animal breeding, how is selection differential defined?

What is the response to selection?

What is the relationship between heritability, selection, and the response to selection?

What is the Breeder’s equation?

Be able to use the Breeder’s equations to solve for each of these three variables