Table 2.

Likelihood Ratio Between Different Evolutionary Models

Evolutionary model	Degree of freedom	X2	P
M0 vs. M2	2	67.06	≪0.0001
M1 vs. M2	2	30.88	≪0.0001

Degree of freedom is the difference in the number of parameters between models.

χ² is twice the difference of log likelihood between models.

P is the probability that two models should differ in log likelihood, as much as that observed, given the degree of freedom.