Tnr8, a foldback transposable element from rice

An insertion sequence 418 bp in length was found in one member of rice retr oposon p-SINE1 in Oryza glaberrima. This sequence had long terminal inverte d repeats (TIRs) and is flanked by direct repeats of a 9-bp sequence at the target site, indicative that the insertion sequence is a rice transposable element, which we named Tnr8. Interestingly, each TIR sequence consisted o f a unique 9-bp terminal sequence and six tandem repeats of a sequence abou t 30 bp in length, like the foldback transposable element first identified in Drosophila. A homology search of databases and analysis by PCR revealed that a large number of Tnr8 members with sequence variations were present i n the rice genome. Some of these members were not present at given loci in several rice species with the AA genome. These findings suggest that the Tn r8 family members transposed long ago, but some appear to have mobilized af ter rice strains with the AA genome diverged. The Tnr8 members are thought to be involved in rearrangements of the rice genome.