Isolation and characterization of the centromeric BAC clones from differnet genomes in genus Oryza

Centromeres play an important role in ensuring the correct segregation and transmission of chromosome during mitosis and meiosis in eukaryoyes. In this research, we constructed five BAC libraries for dilpoid wild rice with different genomes. Together with the technique of colony blot hybridization and fluorescence in situ hybridization (FISH), centro- mere-related BAC clones were screened and characterized from different genomes. Meanwhile, co-hybridization was de- tected between these clones and the five genomes. The results from this study demonstrated that: (1) there were centro- mere-specific satellite repeat in Oryza officinalis (CC genome) and O. brachyantha (FF genome), respectively, and centro- mere-specific CRR-related sequence was found in O. brachyantha; (2) homology sequences of CentO and CRR of O. sativa (AA genome) were detected on all centromeres of O. glaberrima (AA genome), O. punctata (BB genome) and O. aus- traliensis (EE genome); And (3) the two somatic chromosomes of O. officinalis comprised of homology sequences of CentO satellites as revealed FISH analysis probed with RCS2. Homology sequences of CRR of O. sativa were also detected on all centromeres of O. officinalis. The results provided a foundation toward cloning the centromeric sequences from dif- ferent genomes of genus Oryza, studying centromere organization and evolution of different genome, analyzing the rela- tionship between centromeric structure and function among different genome.