title: Chromosomal organization of a sequence related to LTR-like elements of Ty1-copia retrotransposons in Avena species.
abstract: A repetitive sequence, pAs17, was isolated from Avena strigosa (As genome) and characterized. The insert was 646 bp in length and showed 54% AT content. Databank searches revealed its high homology to the long terminal repeat (LTR) sequences of the specific family of Ty1-copia retrotransposons represented by WIS2-1A and Bare. It was also found to be 70% identical to the LTR domain of the WIS2-1A retroelement of wheat and 67% identical to the Bare-1 retroelement of barley. Southern hybridizations of pAs17 to diploid (A or C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) oat species revealed that it was absent in the C diploid species. Slot-blot analysis suggested that both diploid and tetraploid oat species contained 1.3 x 10(4) copies, indicating that they are a component of the A-genome chromosomes. The hexaploid species contained 2.4 x 10(4) copies, indicating that they are a component of both A- and D-genome chromosomes. This was confirmed by fluorescent in situ hybridization analyses using pAs17, two ribosomal sequences, and a C-genome specific sequence as probes. Further, the chromosomes involved in three C-A and three C-D intergenomic translocations in Avena murphyi (AC genomes) and Avena sativa cv. Extra Klock (ACD genomes), respectively, were identified. Based on its physical distribution and Southern hybridization patterns, a parental retrotransposon represented by pAs17 appears to have been active at least once during the evolution of the A genome in species of the Avena genus.
authors.affiliation: Department of Cell Biology and Genetics, University of Alcalá, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Linares
authors.forename: A
authors.initials: A
authors.lastname: Serna
authors.forename: A
authors.initials: A
authors.lastname: Fominaya
mesh_terms: D018554:Avena / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D016208:Databases, Factual; D018745:Genome, Plant; D008969:Molecular Sequence Data; D018626:Retroelements; D012689:Sequence Homology, Nucleic Acid; D020079:Terminal Repeat Sequences
chemical_list: D018626:Retroelements