Plant & Animal Genome IX Conference

Poster: Sequencing & EST
P01_69.html

ANALYSIS OF A 2.9-MBP REGION ENCOMPASSING 12 CM IN RICE CHROMOSOME 10

The Plant Genome Initiative at Rutgers, Waksman Institute Rutgers, The State University of New Jersey Piscataway, NJ 08854-8020. http://pgir.rutgers.edu

Rice (Oryza sativa L.) has been considered an ideal model system for the study of grasses based on its commercial value, relative small genome size (~490 Mb), diploid origin (2X =24), and close relationship to other important cereal crops. As part of an international effort to sequence the genome of rice, we are sequencing 2.9 Mb of contiguous sequence encompassing 12 cM of chromosome 10. Here, we report our progress towards the characterization of this segment, extending from positions 29.8 to 41.8. Here, we report the number and distribution of transposons, retrotransposons and MITEs as well as the number and density of genes in this genomic segment. While the average physical-to-genetic distance ratio (240 kbp/cM) is close to that estimated for the entire rice genome, there are extreme positional differences. The 300-kb region proximal to the centromere showed suppression of recombination while recombination frequencies further away approached values observed in other gene-dense regions of cereal genomes (100 kb/cM). Supression of recombination is correlated to the presence of retrotransposable elements. There is an uneven distribution of genes, with gene-dense segments showing elevated levels of recombination. Evolutionary and practical aspects of these findings will be discussed.