STABILITY OF HOR1-SPECIFIC YAC-CLONES AND PHYSICAL MAPPING OF HOR1-LOCI IN BARLEY

The hordeins are the major class of storage proteins in barley and are encoded by multigene families. Two YAC-clones specific for the C-hord ein-coding Hor1-locus of barley (Hordeum vulgare L.) were selected. Th e clones were constructed with DNA from the cultivars 'Franka' and 'Ho ckey' and have insert sizes of 330 kb and 350 kb, respectively. Perfor ming partial digestions and hybridizations with vector-specific probes , a restriction analysis was conducted using restriction enzymes with a 8-bp recognition sequence. Both clones cover the complete region of the Hor1-locus, but exhibit a different pattern of restriction sites r eflecting the polymorphic nature of the locus on the scale of long-ran ge restriction mapping. The maximal extent of the regions homologous t o the Hor1-specific probe, pBSC5, was 105 kb in the 'Hockey'-derived Y AC and 190 kb in the yeast artificial chromosome constructed with ''Fr anka'-DNA. Furthermore the high degree of instability observed with th e Hor1-specific YAC-clones is discussed in conjunction with the struct ure of the Hor1-locus.