To facilitate chromosome walking with the BAC system, methods were developed to isolate the proximal ends of restriction fragments inserted into the BAC vector and used to isolate both the left and right ends of six randomly selected BAC clones. These results demonstrate that the S. bicolor BAC library will be useful for several physical mapping and map-based cloning applications not only in sorghum but other related cereal genomes, such as maize. Furthermore, we conclude that the BAC system is suitable for most large genome applications, is more 'user friendly' than the YAC system, and will likely lead to rapid progress in cloning biologically significant genes from plants. Zhang, H.B., S.D. Choi, S.S. Woo, Z.K. Li, and R.A. Wing. 1996. Construction and characterization of two rice bacterial artificial chromosome libraries from the parents of a permanent recombinant inbred mapping population.
Rice is a leading grain crop and the staple food for over half the world population.
Rice is also an ideal species for genetic and biological studies for cereal crops and other monocotyledonous plants because of its small genome and well developed genetic system. The Lemont library contains 7296 clones with an average insert size of 150 kb, which represents 2.6 rice haploid genome equivalents. The Teqing library contains 14,208 clones with an average insert size of 130 kb, which represents 4.4 rice haploid genome equivalents. Three single copy DNA probes were used to screen the libraries and at least two overlapping BAC clones were isolated with each probe from each library, ranging from 45 to 260 kb in insert size. Hybridization of BAC clones with chloroplast DNA probes and fluorescent in situ hybridization using BAC DNA as probes demonstrated that both libraries contain very few clones of chloroplast DNA origin and are likely free of chimeric clones.