title: Gene conversion shapes linear mitochondrial genome architecture.
abstract: Recently, it was shown that gene conversion between the ends of linear mitochondrial chromosomes can cause telomere expansion and the duplication of subtelomeric loci. However, it is not yet known how widespread this phenomenon is and how significantly it has impacted organelle genome architecture. Using linear mitochondrial DNAs and mitochondrial plasmids from diverse eukaryotes, we argue that telomeric recombination has played a major role in fashioning linear organelle chromosomes. We find that mitochondrial telomeres frequently expand into subtelomeric regions, resulting in gene duplications, homogenizations, and/or fragmentations. We suggest that these features are a product of subtelomeric gene conversion, provide a hypothetical model for this process, and employ genetic diversity data to support the idea that the greater the effective population size the greater the potential for gene conversion between subtelomeric loci.
authors.affiliation: Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, Canada. smithdr@dal.ca
authors.forename: David Roy
authors.initials: DR
authors.lastname: Smith
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Keeling
mesh_terms: D002875:Chromosomes / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics; D019143:Evolution, Molecular; D005785:Gene Conversion / Q000235:genetics*; D020440:Gene Duplication; D014644:Genetic Variation; D054629:Genome, Mitochondrial; D010957:Plasmids / Q000235:genetics; D011995:Recombination, Genetic; D016615:Telomere
chemical_list: D004272:DNA, Mitochondrial
keywords: gene duplication; inverted repeat; mitochondrial DNA; nucleotide diversity; plasmid; telomere