Synopsis:
Why children resemble their parents, through the concept of heritability
In this lecture, the main theme is the concept of heritability. I use survey data from my class, both this semester and over several years, to examine stature in the students and their parents. I illustrate the idea of the normal distribution with stature data, and discuss the reasons why continuously measured traits often fit that distribution. Also, I define the idea of "regression to the mean" and discuss its relation to inheritance.
This is a continuing experiment in sharing the lectures for the course online. For my explainer, you can see Lecture 2: Feet.
Study questions:
- Why do you think human populations are different in their average statures?
- Can you list some traits that have lower heritability than stature in humans? What would the relationship of parent and offspring values look like for these traits?
- What would be a trait that has zero heritability?
- How can animal breeders manage to increase the value of traits like milk production in their animals, if regression to the mean ensures that the highest-producing animals will have offspring with lower mean values for such traits?