Phylogenetic analyses suggest lateral gene transfer from the mitochondrion to the apicoplast

• Published in: Gene Vol. 285; no. 1; pp. 109 - 118
• Main Authors: Obornı́k, Miroslav, Van de Peer, Yves, Hypša, Václav, Frickey, Tancred, Šlapeta, Jan R., Meyer, Axel, Lukeš, Julius
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20-02-2002
• Subjects: Animals; Apicoplast; apicoplasts; Base Composition; DNA, Mitochondrial - genetics; DNA, Protozoan - genetics; Evolution, Molecular; Gene transfer; Genes, Protozoan - genetics; Hybrid genome; Mitochondrion; Organelles - genetics; Phylogeny; Plasmodium falciparum - genetics; Plastid; Plastids - genetics; Protozoan Proteins - genetics; Ribosomal protein; Ribosomal Proteins - genetics; Toxoplasma - genetics; aa, amino acid(s); rps8, gene for ribosomal protein S8; Plastid; rbcL, gene for ribulose-1,5-bisphosphate carboxylase, large subunit; tufA, gene for elongation factor Tu; rps12, gene for ribosomal protein S12; ML, maximum likelihood (optimality criterion); rpl14, gene for ribosomal protein L14; LBA, long branch attraction; rpl11, gene for ribosomal protein L11; AT, adenosine+thymidine; rpoB, gene for RNA polymerase, subunit B; kb, kilobase(s); MP, maximum parsimony (optimality criterion); Hybrid genome; clpC, gene for caseinolytic protease C; lsu, large subunit; rpl2, gene for ribosomal protein L2; Apicoplast; rp(s), gene for ribosomal protein(s); ssu, smal subunit; Gene transfer; rRNA, ribosomal RNA; ycf24, gene for ycf24 protein; tRNA, gene for transfer RNA; Ribosomal protein; Mitochondrion; nt, nucleotide(s); pl, plastid; D, distance (optimality criterion); mt, mitochondrial; rpoC, gene for RNA polymerase, subunit C
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/S0378-1119(02)00427-4

Apicomplexan protozoa contain a single mitochondrion and a multimembranous plastid-like organelle termed apicoplast. The size of the apicomplexan plastid genome is extremely small (35 kb) thus offering a limited number of genes for phylogenetic analysis. Moreover, the sequences of apicoplast genes are highly adenosine+thymidine-rich and rapidly evolving. Due to these facts, phylogenetic analyses based on different genes or the structure of the ribosomal operon show conflicting results and the evolutionary history of this exciting organelle remains unclear. Although it is evident that the apicoplast and its genome is plastid-derived, our detailed phylogenetic analysis of amino acid and nucleotide sequences of selected apicoplast ribosomal protein genes
rpl2,
rpl14 and
rps12 show their possible mitochondrial origin. The affinity of apicoplast ribosomal proteins to their mitochondrial homologs is very stable and well supported. Based on our results we propose that apicoplasts might contain both plastid and mitochondrial genes, thus constituting a hybrid assembly.