MOLECULAR-STRUCTURE OF A WHEAT CHROMOSOME END HEALED AFTER GAMETOCIDAL GENE-INDUCED BREAKAGE

In the progeny of the monosomic addition line of common wheat, Triticu m aestivum, carrying the game-tocidal chromosome of Aegilops cylindric a, deletion chromosomes carrying the break point within the nucleolar organizing region of chromosome 1B appeared, Attempts were made to amp lify the break points by PCR using primers of telomere and rDNA (rRNA gene), In one deletion line, specific amplification of DNA fragments i ncluding the 18S rRNA gene, telomere repeats, and their junction occur red, At the junction of telomere and rRNA gene there was a 31-bp Inver ted duplication of tile rRNA gene, Telomere sequences were initiated f rom the sequence TAG in the duplication. Between the duplications a sm all sequence was also inserted, This novel DNA sequence at the break p oint indicates that the breakage-fusion-bridge cycle(s) took place aft er the first chromatin breakage by the gametocidal gene.