Zhong Xia QI, Hui ZENG, Xiu Lan LI, Cheng Bin CHEN, Wen QiN SONG, Rui Yang CHEN^*

The origin and evolution of B chromosomes could be explained by the specific DNA sequence on them. But the specific sequences known were quite limited. To investigate maize B chromosome sqicific DNA sequeces, maize genomes with and without B chromosomes were analyzed by AFLP. Only 5 markers were found specific to genomes with B chromosomes among about 2000 AFLP markers. Southern hybridization and sequence analysis revealed that only the sequence of M8-2D was a B chromosome specific sequence. This sequence contained the telomeric repeat unit AGGGTTT conserved in plant chromosome telomeres. In addition, the sequence of M8-2D shared low homology to clones from maize chromosome 4 centromere as well. M8-2D were localized to B chromosome centromeric and telomeric regions.