Figure 1. Simple examples.

A. An example tree. B. The covariance matrix implied by the tree structure in A. Note that the covariance here is with respect to the allele frequency at the root, and that each entry has been divided by to simplify the presentation. C. An example graph. The migration edge is colored red. Parental populations for population 3 are labeled and ; see the main text for details. D. The covariance matrix implied by the graph in C; again, each entry has been divided by . The migration terms are in red, and the non-migration terms are in blue.