Preecha Prathepha and Supachai Samappito

pp. 39 - 48

Abstract

In a previous study we described the prevalence and distribution in Thailand of the retroposon pSINE1-r2, in the intron 10 of the waxy gene in cultivated and wild rice with the AA genome. In this study, additional varieties of rice were collected and sequencing was used to further characterize p-SINE1-r2. It was found that the length of the p-SINE1-r2 nucleotide sequences was about 125 bp, flanked by identical direct repeats of a 14 bp sequence. These sequences were compared and found to be similar to the sequences of pSINE1-r2 found in Nipponbare, a rice strain discussed in a separate study. However, when compared the 48 DNA sequences identified in this study, much dissimilarity was found within the nucleotide sequences of pSINE1-r2, in the form of base substitution mutations. Phylogenetic relationships inferred from the nucleotide sequences of these elements in cultivated rice (O. sativa) and wild rice (O. nivara). It was found that rice accessions collected from the same geographical distribution have been placed in the same clade. The phylogenetic tree supports the origin and distribution of these rice strains.