Concerted evolution of duplicated mitochondrial control regions in three related seabird species.
BACKGROUND
Many population genetic and phylogenetic analyses of mitochondrial DNA (mtDNA) assume that mitochondrial genomes do not undergo recombination. Recently, concerted evolution of duplicated mitochondrial control regions has been documented in a range of taxa. Although the molecular mechanism that facilitates concerted evolution is unknown, all proposed mechanisms involve mtDNA recombination.


RESULTS
Here, we document a duplication of a large region (cytochrome b, tRNAThr, tRNAPro, ND6, tRNAGlu and the control region) in the mitochondrial genome of three related seabird species. To investigate the evolution of duplicate control regions, we sequenced both control region copies (CR1 and CR2) from 21 brown (Sula leucogaster), 21 red-footed (S. sula) and 21 blue-footed boobies (S. nebouxii). Phylogenetic analysis suggested that the duplicated control regions are predominantly evolving in concert; however, approximately 51 base pairs at the 5' end of CR1 and CR2 exhibited a discordant phylogenetic signal and appeared to be evolving independently.


CONCLUSIONS
Both the structure of the duplicated region and the conflicting phylogenetic signals are remarkably similar to a pattern found in Thalassarche albatrosses, which are united with boobies in a large clade that includes all procellariiform and most pelecaniform seabirds. Therefore we suggest that concerted evolution of duplicated control regions either is taxonomically widespread within seabirds, or that it has evolved many times.
Morris-Pocock
James A
JA
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada. 0jam3@queensu.ca
Taylor
Scott A
SA
Birt
Tim P
TP
Friesen
Vicki L
VL
D000818:Animals; D001499:Bayes Theorem; D001717:Birds / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D054629:Genome, Mitochondrial; D016013:Likelihood Functions; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial