title: Genome-wide analysis reveals origin of transfer RNA genes from tRNA halves.
abstract: Transfer RNAs (tRNAs) play an important role linking mitochondrial RNA and amino acids during protein biogenesis. Four types of tRNA genes have been identified in living organisms. However, the evolutionary origin of tRNAs remains largely unknown. In this article, we conduct a deep sequence analysis of diverse genomes that cover all three domains of life to unveil the evolutionary history of tRNA genes from tRNA halves. tRNA half homologs were detected in diverse organisms, and some of them were expressed in mouse tissues. Continuous tRNA genes have a conserved pattern similar to indels, which is, more closely flanking regions have higher single nucleotide substitution rates, whereas tRNA half homologs do not have this pattern. In addition, tRNAs tend to break into tRNA halves when tissues are incubated in vitro, the tendency of tRNA to break into tRNA halves may be a "side-effect" of tRNA genes evolving from tRNA halves. These results suggest that modern tRNAs originated from tRNA halves through a repeat element-mediated mechanism. These findings provide insight into the evolutionary origin of tRNA genes.
authors.affiliation: Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Zuo
authors.forename: Duo
authors.initials: D
authors.lastname: Peng
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Yin
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhou
authors.forename: Hanhua
authors.initials: H
authors.lastname: Cheng
authors.forename: Rongjia
authors.initials: R
authors.lastname: Zhou
mesh_terms: D039903:Actinobacteria / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D004331:Drosophila melanogaster / Q000235:genetics; D019143:Evolution, Molecular; D016678:Genome; D055106:Genome-Wide Association Study; D006801:Humans; D008253:Macaca mulatta / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D002679:Pan troglodytes / Q000235:genetics; D010802:Phylogeny; D012313:RNA / Q000145:classification / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012343:RNA, Transfer / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D051381:Rats; D017423:Sequence Analysis, RNA
chemical_list: D000077278:RNA, Mitochondrial; D012313:RNA; D012343:RNA, Transfer
keywords: expression; indels; repeat elements; tRNA