Molecular cytogenetic physical mapping of Sorghum bicolor chromosomes.

摘要

S. bicolor (Moench.) BAC clones were selected from the TAMU sorghum BAC library after screening with twenty three PUC18 clones previously used to construct a sorghum RFLP map and two cDNA clones, one containing the sorghum alcohol dehydrogenase (adh) gene, and the other the maize shrunken-2 ;FISH of the selected BAC clones collectively marked 19 single-copy sites on seven different chromosomes. One marked chromosome D;BACs 22 B2 (45 Kb) and 128 H4 preferentially hybridized to centromeric regions. Moreover, hybridization was much stronger on 5 of the 10 pairs of S. bicolor chromosomes, providing extremely strong evidence that S. bicolor is tetraploid, with five chromosomes per set. Each set of five chromosomes can be termed a subgenome. Both, molecular recombinational mapping and physical mapping utilizing FISH of RFLP-selected BACs suggest that extensive rearrangement has occurred among the sorghum chromosomes following polyploidization.