GENOME-SPECIFIC REPETITIVE DNA AND RAPD MARKERS FOR GENOME IDENTIFICATION IN ELYMUS AND HORDELYMUS

We have developed RFLP and RAPD markers specific for the genomes invol ved in the evolution of Elymus species, i.e., the St, Y, H, P, and W g enomes. Two P genome specific repetitive DNA sequences, pAgc1 (350 bp) and pAgc30 (455 bp), and three W genome specific sequences, pAnv3 (22 1 bp), pAuv7 (200 bp), and pAuv13 (207 bp), were isolated from the gen omes of Agropyron cristatum and Australopyrum velutinum, respectively. Attempts to find Y genome specific sequences were not successful. Pri mary-structure analysis demonstrated that pAgc1 (P genome) and pAgc30 (P genome) share 81% similarity over a 227-bp stretch. The three W gen ome specific sequences were also highly homologous. Sequence compariso n analysis revealed no homology to sequences in the EMBL-GenBank datab ases. Three to four genome-specific RAPD markers were found for each o f the five genomes. Genome-specific bands were cloned and demonstrated to be mainly low-copy sequences present in various Triticeae species. The RFLP and RAPD markers obtained, together with the previously desc ribed H and St genome specific clones pHch2 and pP1Taq2.5 and the Ns g enome specific RAPD markers were used to investigate the genomic compo sition of a few Elymus species and Hordelymus euraeus, whose genome fo rmulas were unknown. Our results demonstrate that only three of eight Elymus species examined (the tetraploid species Elymus grandis and the hexaploid species Elymus caesifolius and Elymus borianus) really belo ng to Elymus.