Molecular Phylogenetics of Western North American Frogs of the Rana boylii Species Group

Authors

J. Robert Macey, Washington University, St. LouisFollow
Jared L. Strasburg, Washington University, St. Louis,
Jennifer A. Brisson, University of Nebraska - LincolnFollow
Vance T. Vredenburg, University of California, Berkeley
Mark Jennings, Rana Resources, Davis, California
Allan Larson, Washington UniversityFollow

Document Type

Article

Date of this Version

4-2001

Comments

Published in Molecular Phylogenetics and Evolution 19:1 (April 2001), pp. 131–143; doi: 10.1006/mpev.2000.0908 Copyright © 2001 by Academic Press. Used by permission. http://www.idealibrary.com

Abstract

Phylogenetic relationships among frogs of the genus Rana from western North America are investigated using 2013 aligned bases of mitochondrial DNA sequence from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA^Ile, tRNA^Gln, tRNA^Met, ND2, tRNA^Trp, tRNA^Ala, tRNA^Asn, tRNA^Cys, tRNA^Tyr, and COI (subunit I of cytochrome c oxidase), plus the origin for light-strand replication (OL) between the tRNA^Asn and tRNA^Cys genes. The aligned sequences contain 401 phylogenetically informative characters. A well-resolved phylogenetic hypothesis in which the Rana boylii species group (R. aurora, R. boylii, R. cascadae, R. muscosa, and R. pretiosa) is monophyletic is obtained. Molecular sequence divergence suggests that the R. boylii species group is approximately 8 million years old. The traditional hypothesis showing monophyly of the yellow-legged frogs (R. boylii and R. muscosa) is statistically rejected in favor of a hypothesis in which R. aurora, R. cascadae, and R. muscosa form a clade. Reanalyses of published nuclear ribosomal DNA restriction-site data and allozymic data support a monophyletic R. boylii group, but do not effectively resolve relationships among species within this group. Eight populations of R. muscosa form two major clades separated by a biogeographic break in the Sierra Nevada of California. This biogeographic break is broadly concordant with breaks found in four other amphibian and reptilian taxa. The two major clades within R. muscosa are estimated to have diverged approximately 2.2 million years before present. Each of these major clades contains two subgroups showing approximately 1.5 million years divergence, implicating climatic effects of Pleistocene glaciation in vicariance. The four distinct subgroups of R. muscosa separated by at least 1.4 million years of evolutionary divergence are suggested as potential units for conservation.