title: GalEa retrotransposons from galatheid squat lobsters (Decapoda, Anomura) define a new clade of Ty1/copia-like elements restricted to aquatic species.
abstract: Crustacean species have not been examined in great detail for their transposable elements content. Here we focus on galatheid crabs, which are one of the most diverse and widespread taxonomic groups of Decapoda. Ty1/copia retrotransposons are a diverse and taxonomically dispersed group. Using degenerate primers, we isolated several DNA fragments that show homology with Ty1/copia retroelements reverse transcriptase gene. We named the corresponding elements from which they originated GalEa1 to GalEa3 and analyzed one of them further by isolating various clones containing segments of GalEa1. This is the first LTR retrotransposon described in crustacean genome. Nucleotide sequencing of the clones revealed that GalEa1 has LTRs (124 bp) and that the internal sequence (4,421 bp) includes a single large ORF containing gag and pol regions. Further screening identified highly related elements in six of the nine galatheid species studied. By performing BLAST searches on genome databases, we could also identify GalEa-like elements in some fishes and Urochordata genomes. These elements define a new clade of Ty1/copia retrotransposons that differs from all other Ty1/copia elements and that seems to be restricted to aquatic species.
authors.affiliation: UMR 7138 Systématique Adaptation Evolution, Equipe Génétique et Evolution, Université Pierre and Marie Curie Paris 6, Case 5, Bât A, porte 427, 7 quai St-Bernard, 75252, Paris Cedex 05, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Terrat
authors.forename: Eric
authors.initials: E
authors.lastname: Bonnivard
authors.forename: Dominique
authors.initials: D
authors.lastname: Higuet
mesh_terms: D000818:Animals; D033381:Anomura / Q000145:classification / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D016678:Genome; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D018626:Retroelements / Q000235:genetics*; D013045:Species Specificity; D020079:Terminal Repeat Sequences
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S; D018626:Retroelements