GENERATION AND CHARACTERIZATION OF A BAC LIBRARY FROM THE MAIZE INBRED LINE B73 FOR MAIZE GENOMICS RESEARCH

Department of Soil & Crop Sciences and Crop Biotechnology Center, Texas A&M University, College Station, TX 77843-2474 USA

Maize is an economically very important crop worldwide and has a genome size of about 2,500 Mb / 1C. To facilitate genomics research of this crop, we have developed a BAC library from the nucleic DNA of the maize inbred line B73, the model line for maize genetic and biological studies. The library contains over 1,000,000 clones with an average insert size of about 150 kb. Over 101,376 BACs have been ordered individually in 264 384-well microtiter dishes, which represents > 6 x maize haploid genomes. In previous studies, we developed a complete set of technologies for rapid development of physical maps of genomes from large-insert bacterial clones and experimentally demonstrated that physical mapping of genomes by fingerprint analysis of large-insert bacterial clones is not significantly influenced by genome size and complexity. With these technologies, we have successfully developed the physical maps of the rice and Arabidopsis genomes in two scientist-years at a cost of about $20,000 for materials and supplies. Because of this, we have tested the feasibility of developing a physical map of the maize genome from the B73 BAC library by fingerprint analysis. The result showed that the large-insert bacterial clone fingerprint analysis approach that we previously developed is well-suited to development of the maize genome physical map from the maize B73 BAC library. According to our research experience in the development of the physical maps of the rice and Arabidopsis genomes, a physical map of the maize genome with a genome coverage of > 95% could be developed by six-eight scientist-years. We are also testing the feasibility of using the maize BAC library to bridge the maize genomics research with our rice genome physical map. This maize BAC library has also provided a valuable resource for other areas of maize genomics research.