Affiliation:
1. Genetics, Evolution, and Molecular Systematics Laboratory, Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada.
2. Northwest Atlantic Fisheries Centre, Department of Fisheries and Oceans, Canada, P.O. Box 5667, St. John’s, NL A1C 5X1, Canada.
Abstract
Phylogenetic analysis of 13 substantially complete mitochondrial DNA genome sequences (14 036 bp) from 10 taxa of gadine codfishes and pollock provides highly corroborated resolution of outstanding questions on their biogeographic evolution. Of 6 resolvable nodes among species, 4 were supported by >95% of bootstrap replications in parsimony, distance, likelihood, and similarly high posterior probabilities in bayesian analyses, one by 85%–95% according to the method of analysis, and one by 99% by one method and a majority of the other two. The endemic Pacific species, walleye pollock (Theragra chalcogramma), is more closely related to the endemic Atlantic species, Atlantic cod (Gadus macrocephalus), than either is to a second Pacific endemic, Pacific cod (Gadus macrocephalus). The walleye pollock should thus be referred to the genus Gadus as originally described (Gadus chalcogrammus Pallas 1811). Arcto-Atlantic Greenland cod, previously regarded as a distinct species (G. ogac), are a genomically distinguishable subspecies within pan-Pacific G. macrocephalus. Of the 2 endemic Arctic Ocean genera, Polar cod (Boreogadus) as the outgroup to Arctic cod (Arctogadus) and Gadus sensu lato is more strongly supported than a pairing of Boreogadus and Arctogadus as sister taxa. Taking into consideration historical patterns of hydrogeography, we outline a hypothesis of the origin of the 2 endemic Pacific species as independent but simultaneous invasions through the Bering Strait from an Arcto-Atlantic ancestral lineage. In contrast to the genome data, the complete proteome sequence (3830 amino acids) resolved only 3 nodes with >95% confidence, and placed Alaska pollock outside the Gadus clade owing to reversal mutations in the ND5 locus that restore ancestral, non-Gadus, amino acid residues in that species.
Publisher
Canadian Science Publishing
Subject
Genetics,Molecular Biology,General Medicine,Biotechnology
Reference56 articles.
1. Mitochondrial Cytochrome b DNA Variation in the High-Fecundity Atlantic Cod: Trans-Atlantic Clines and Shallow Gene Genealogy
2. Molecular Phylogenetics of Gadidae and Related Gadiformes Based on Mitochondrial DNA Sequences
3. Bermingham, E., McAfferty, S.S., and Martin, A.P. 1997. Fish biogeography and molecular clocks: perspectives from the Panamanian isthmus. In Molecular systematics of fishes. Edited by T.D. Kocher and C.A. Stepien. Academic Press, San Diego, Calif. pp. 113–126.
4. Carr, S.M., and Crutcher, D.C. 1998. Population genetic structure in Atlantic cod (Gadus morhua) from the North Atlantic and Barents Sea: contrasting or concordant patterns in mtDNA sequence and microsatellite data? In The implications of localized fishery stocks. Edited by I. Hunt von Herbing, I. Kornfield, M. Tupper, and J. Wilson. Northeast Regional Agricultural Engineering Service, Ithaca, N.Y. pp. 91–103.
Cited by
85 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献