title: Genes and processed paralogs co-exist in plant mitochondria.
abstract: RNA-mediated gene duplication has been proposed to create processed paralogs in the plant mitochondrial genome. A processed paralog may retain signatures left by the maturation process of its RNA precursor, such as intron removal and no need of RNA editing. Whereas it is well documented that an RNA intermediary is involved in the transfer of mitochondrial genes to the nucleus, no direct evidence exists for insertion of processed paralogs in the mitochondria (i.e., processed and un-processed genes have never been found simultaneously in the mitochondrial genome). In this study, we sequenced a region of the mitochondrial gene nad1, and identified a number of taxa were two different copies of the region co-occur in the mitochondria. The two nad1 paralogs differed in their (a) presence or absence of a group II intron, and (b) number of edited sites. Thus, this work provides the first evidence of co-existence of processed paralogs and their precursors within the plant mitochondrial genome. In addition, mapping the presence/absence of the paralogs provides indirect evidence of RNA-mediated gene duplication as an essential process shaping the mitochondrial genome in plants.
authors.affiliation: Botanical Garden, Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83 Opg. S, 1307, Copenhagen K, Denmark. argelia.cuenca@gmail.com
authors.forename: Argelia
authors.initials: A
authors.lastname: Cuenca
authors.forename: Gitte
authors.initials: G
authors.lastname: Petersen
authors.forename: Ole
authors.initials: O
authors.lastname: Seberg
authors.forename: Anne Hoppe
authors.initials: AH
authors.lastname: Jahren
mesh_terms: D035961:Alismatales / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D022761:Gene Transfer, Horizontal; D050259:Genes, Mitochondrial; D017343:Genes, Plant; D018745:Genome, Plant; D008928:Mitochondria / Q000235:genetics; D010802:Phylogeny; D017393:RNA Editing