CLONING AND GENETIC-MAPPING OF WHEAT TELOMERE-ASSOCIATED SEQUENCES

Wheat telomere-associated sequences (TASs) were cloned using a Vectore tte approach and sequenced. Reverse primers specific to the TASs were combined with labelled degenerate telomere primers in PCR reactions co ntaining total genomic DNA as template. Amplification products were se parated on sequencing gels. In total, seventeen primer combinations pr ovided 47 polymorphic fragments. Nine of these mapped beyond the most distal RFLP markers and defined the ends of seven chromosome arms. Sev en of the nine terminal fragments were derived from a 118-bp tandem re peat, indicating that subtelomeric tandem repeat sequences provide an efficient means to target chromosome ends. A telomere cloning strategy and the terminal and interstitial location of TASs are discussed.