RAPD analysis was performed to assess DNA variation among rye plants regene
rated from immature embryos and inflorescences. From the studied plants, 40
% showed at least one variation, and the number of mutations per plant was
quite high, ranging from 1 up to 12. On some occasions (2.9% of the scored
bands) the modified band was observed in only one plant or in several but o
riginated from the same callus (variable band). In other cases (5.25%) the
same band varied in several plants obtained from different calli. We call t
hese hypervariable bands and they could vary between plants belonging to di
fferent cultivars and/or with different origins, inflorescences or embryos.
Thus, they must originate through independent mutational events. We assume
that. these bands represent hypervariable regions of the rye genome and so
detect hot spots of DNA instability. Some of these bands proved to be uniq
ue sequences, others were present in a low copy number while the remaining
ones were moderately or highly repetitive.