Cloning and genetic mapping of wheat telomere-associated sequences

Wheat telomere-associated sequences (TASs) were cloned using a Vectorette approach and sequenced. Reverse primers specific to the TASs were combined with labelled degenerate telomere primers in PCR reactions containing total genomic DNA as template. Amplification products were separated on sequencing gels. In total, seventeen primer combinations provided 47 polymorphic fragments. Nine of these mapped beyond the most distal RFLP markers and defined the ends of seven chromosome arms. Seven of the nine terminal fragments were derived from a 118-bp tandem repeat, 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.