title: Dynamic evolution of mitochondrial ribosomal proteins in Holozoa.
abstract: We studied the highly dynamic evolution of mitochondrial ribosomal proteins (MRPs) in Holozoa. Most major clades within Holozoa are characterized by gains and/or losses of MRPs. The usefulness of gains of MRPs as rare genomic changes in phylogenetics is undermined by the high frequency of secondary losses. However, phylogenetic analyses of the MRP sequences provide evidence for the Acrosomata hypothesis, a sister group relationship between Ctenophora and Bilateria. An extensive restructuring of the mitochondrial genome and, as a consequence, of the mitochondrial ribosomes occurred in the ancestor of metazoans. The last MRP genes encoded in the mitochondrial genome were either moved to the nuclear genome or were lost. The strong decrease in size of the mitochondrial genome was probably caused by selection for rapid replication of mitochondrial DNA during oogenesis in the metazoan ancestor. A phylogenetic analysis of MRPL56 sequences provided evidence for a horizontal gene transfer of the corresponding MRP gene between metazoans and Dictyostelidae (Amoebozoa). The hypothesis that the requisition of additional MRPs compensated for a loss of rRNA segments in the mitochondrial ribosomes is corroborated by a significant negative correlation between the number of MRPs and length of the rRNA. Newly acquired MRPs evolved faster than bacterial MRPs and positions in eukaryote-specific MRPs were more strongly affected by coevolution than positions in prokaryotic MRPs in accordance with the necessity to fit these proteins into the pre-existing structure of the mitoribosome.
authors.affiliation: Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
authors.forename: Bettina M
authors.initials: BM
authors.lastname: Scheel
authors.affiliation: Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany. Electronic address: hausdorf@zoologie.uni-hamburg.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hausdorf
mesh_terms: D000656:Amoeba / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D037302:Ctenophora / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal / Q000235:genetics; D054629:Genome, Mitochondrial / Q000235:genetics; D023281:Genomics; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins
keywords: Coevolution; Ctenophora; Holozoa; Horizontal gene transfer; Mitochondrial ribosomal proteins; Placozoa