Clusters of interspersed repeated DNA sequences in the rice genome (Oryza)

Publisher Website
Google Scholar
Abstract
We have characterized a repeated DNA sequence (RTL 122) from rice (Oryza sauva L.) with respect to its organization in the rice genome and its distribution among rice and other plants. The results indicate that the RTL 122 sequence is interspersed in the rice genome and limited to the genus Oryza. It is highly polymorphic and can be used to fingerprint rice varieties. A structure was observed in which several repeated sequences were clustered in DNA regions of 15–20 kb. We characterized three bacteriophage lambda clones that contained the RTL 122 sequence. Southern analysis using probes derived from restriction fragments of the three lambda clones indicated that all fragments except one are interspersed repeated sequences and belong to different repeated sequence families. Subsequent slot blot hybridization showed that most of them are only present within the genus Oryza. Some of the Oryza-specific, physically linked sequences show the same phylogenetic distribution, which suggests that these sequences might have evolved in a coordinate fashion. On the other hand, some of the repeated sequences have a different distribution even though they are physically adjacent in the genome. We speculate that such blocks of interspersed repeated sequences may serve as hotspots for rapid changes in the rice genome.Key words: rice, Oryza, repeated sequences, DNA fingerprinting, coordinated evolution.

This publication has 0 references indexed in Scilit: