Using correlation to estimating heritability

What is the meaning of the correlation coefficient of two distributions? How do you compute it? How is observed correlation related to narrow-sense heritability? How does the relationship depend on the proportion of shared alleles? How can you use a twin study to estimate the broad-sense heritability of a trait?

This video lecture was recorded at the University of Wisconsin -- Stout in the fall of 2021. It accompanies my BIO 332 Genetics course, which was taught with Hartl's "Genetics: Analysis of Genes and Genomes."