title: Testing for equality of evolutionary rates.
abstract: A likelihood ratio test is presented for comparing rates of evolutionary change in the paths of descent leading to two species. The test is compared to previous relative rate tests based on variances of estimated numbers of base substitutions. The likelihood approach allows for different transversion and transition rates, and when these rates are actually different, the likelihood ratio test can be much more powerful than the variance-based tests. For single-parameter mutation models, however, the two tests have similar power. The tests are applied to a set of chloroplast sequences from several species of grasses, and additional indications of significantly different rates leading to barley were found with the likelihood ratio test.
authors.affiliation: Department of Statistics, North Carolina State University, Raleigh 27695-8203.
authors.forename: S V
authors.initials: SV
authors.lastname: Muse
authors.forename: B S
authors.initials: BS
authors.lastname: Weir
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D002736:Chloroplasts / Q000502:physiology; D016013:Likelihood Functions; D008957:Models, Genetic; D015233:Models, Statistical; D006109:Poaceae / Q000235:genetics* / Q000648:ultrastructure