Plant & Animal Genome VI Conference

P403

TOWARD DEVELOPMENT OF AN INTEGRATED PHYSICAL MAP OF THE RICE GENOME WITH BACs

1. Department of Soil and Crop Sciences, Crop Biotechnology Center, Texas A&M University, College Station, TX 77843-2123, USA
2. Institute of Genetics, Chinese Academy of Sciences, Beijing 100101, P. R. China
3. State Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, P.R. China

Enhanced genomics research of grass crops, including rice, maize and wheat, will hinge on integrative physical mapping of the genomes. An integrated physical map will revolutionize numerous research procedures, including gene mapping, cloning and utilization. In pervious studies we demonstrated the feasibility of physically mapping genomes with BACs and developed a complete set of technologies for rapid development of integrated physical maps of genomes with BACs by BAC fingerprinting, contig assembly and genetic-physical maps integration. Using these technologies, we are developing an integrated physical map for grass crops in which rice serves as the reference species because it has the smallest genome among the grass crops. The long-term goals of this project are to 1) map most (80,000) grass genes and ESTs at a resolution of about 20 kb within a few years, 2) clone a number of agronomic grass genes and QTLs, and 3) conduct molecular analysis of the grass genomes. We have developed four rice BAC libraries of 130-150 kb and fingerprinted over 25,000 BACs randomly selected from the three Teqing (Indica) BAC libraries, covering >8x haploid rice genomes. Currently we are assembling the BAC contig physical map. We have also integrated over 300 DNA markers mapped to the rice RFLP maps onto the physical map and additional mapped DNA markers is used in the integration. Because gene content and order are highly conserved in the grass genomes, the results will constitute a seminal integrated physical map for all graminous crops.