Fig 4. Results 1 and 2 give conditions leading to K = u.

(a) Our Result 1 states that the molecular clock has the same rate as in a well-mixed population, K = u, if the rate of turnover d _i is uniform across sites, as in this example (d _i = 0.2 for all i). (b) Result 2 asserts that ρ _i = 1/N for all i—again implying K = u—if and only if each site has birth rate equal to death rate, b _i = d _i for all i, as in this example. Nodes are colored according to their rates of turnover d _i.