Complex arrangement of dispersed repeated DNA sequences in Oryza officinalis

A 525-bp BglII fragment was isolated from Oryza officinalis DNA (accession W1278) and shown to correspond to a new dispersed repetitive DNA sequence with specificity restricted to a subset of the wild rice with a C genome. The sequence of the fragment was determined but it does not correspond to any sequence already present in databases. It contains several imperfect palindromes. Larger genomic clones (12-18 kbp) were isolated and all contain sequences homologous to the BglII element. Analysis of these clones confirms that the BglII element is dispersed in the O. officinalis genome. From one genomic clone, the sequences adjacent to the BglII element were subcloned and used as probes to demonstrate that the sequences flanking the BglII element are variable in different genomic clones and that some of them are also dispersed repetitive sequences. The genomic specificity of two of these dispersed repeats was evaluated and shown to be different from that of the initial BglII element. This analysis revealed a complex arrangement of various dispersed repeated sequences.