title: Identification of Bari Transposons in 23 Sequenced Drosophila Genomes Reveals Novel Structural Variants, MITEs and Horizontal Transfer.
abstract: Bari elements are members of the Tc1-mariner superfamily of DNA transposons, originally discovered in Drosophila melanogaster, and subsequently identified in silico in 11 sequenced Drosophila genomes and as experimentally isolated in four non-sequenced Drosophila species. Bari-like elements have been also studied for their mobility both in vivo and in vitro. We analyzed 23 Drosophila genomes and carried out a detailed characterization of the Bari elements identified, including those from the heterochromatic Bari1 cluster in D. melanogaster. We have annotated 401 copies of Bari elements classified either as putatively autonomous or inactive according to the structure of the terminal sequences and the presence of a complete transposase-coding region. Analyses of the integration sites revealed that Bari transposase prefers AT-rich sequences in which the TA target is cleaved and duplicated. Furthermore evaluation of transposon's co-occurrence near the integration sites of Bari elements showed a non-random distribution of other transposable elements. We also unveil the existence of a putatively autonomous Bari1 variant characterized by two identical long Terminal Inverted Repeats, in D. rhopaloa. In addition, we detected MITEs related to Bari transposons in 9 species. Phylogenetic analyses based on transposase gene and the terminal sequences confirmed that Bari-like elements are distributed into three subfamilies. A few inconsistencies in Bari phylogenetic tree with respect to the Drosophila species tree could be explained by the occurrence of horizontal transfer events as also suggested by the results of dS analyses. This study further clarifies the Bari transposon's evolutionary dynamics and increases our understanding on the Tc1-mariner elements' biology.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro" via Orabona 4 70125, Bari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Palazzo
authors.affiliation: Istituto di Biomembrane e Bioenergetica, Consiglio Nazionale delle Ricerche, Via Amendola 165/A, 70126, Bari, Italy.
authors.forename: Domenica
authors.initials: D
authors.lastname: Lovero
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro" via Orabona 4 70125, Bari, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: D'Addabbo
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro" via Orabona 4 70125, Bari, Italy.
authors.forename: Ruggiero
authors.initials: R
authors.lastname: Caizzi
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro" via Orabona 4 70125, Bari, Italy.
authors.forename: René Massimiliano
authors.identifier: 0000-0001-8450-1010
authors.initials: RM
authors.lastname: Marsano
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004251:DNA Transposable Elements / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal / Q000235:genetics*; D014644:Genetic Variation; D049750:Genome, Insect / Q000235:genetics; D016254:Mutagenesis, Insertional / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D020079:Terminal Repeat Sequences
chemical_list: D004251:DNA Transposable Elements