Yeast artificial chromosome clones of rice chromosome 2 ordered using DNA markers

Yeast artificial chromosome (YAC) clones were ordered for the physical mapping of rice chromosome 2, the last of the 12 rice chromosomes to be assigned YACs by the Rice Genome Research Program. A total of 128 restriction fragment length polymorphism markers and 4 sequence-tagged site (STS) markers located on our high-density genetic map were used for YAC clone landing. By colony/Southern hybridization and polymerase chain reaction screening, a total of 239 individual YACs were selected from our YAC library of 6934 clones covering six genome equivalents. The YACs located on the corresponding marker positions in the linkage map formed 43 contigs and islands and were estimated to encompass about 50% of the length of rice chromosome 2.