THE R173 FAMILY OF RYE-SPECIFIC REPETITIVE DNA-SEQUENCES - A STRUCTURAL-ANALYSIS

In contrast to all other characterised families, repetitive DNA sequences of the rye-specific R173 family occur generally as a monomer and have an unusually long repeat unit. A genomic library was generated from a wheat line with three copies of the short arm of chromosome 1 of rye, 1RS. Seventy-seven lambda clones, representing independent members of the family, were isolated by hybridization to pAW173. They share a common region of approximately 3.5 kbp, which is free of large internal repeats and therefore constitutes the basic unit of the dispersed R173 family. The analysis of flanking regions showed that individual members of the R173 family are generally not found in the vicinity of other characterised families of repetitive DNA. The flanking regions of four selected lambda clones were different from each other and comprised both repetitive and low-copy sequences. A restriction fragment length polymorphism probe, mapping to the short arm of chromosome 1, was obtained by subcloning of flanking regions of the R173 family.