Is there a connection between genomic changes and wide hybridization?

The structural organization of a set of highly repetitive DNA sequences (HRS) of barley (Hordeum vulgare) was studied by blot-hybridization in the genomes of seven Hordeum L. species and several Hordeum x Secale hybrids. The copy numbers of the sequences, and length and intensity of the hybridization fragments varied among barley species; so, this set appeared to be useful as molecular markers for barley species. Structural rearrangements of some HRS were observed in hybrids. It was noteworthy that the genomic changes in the hybrids partially coincided with those that take place during species divergence; so, chromosomal rearrangements are likely to proceed according to certain rules. The possibility of cryptic mobile elements participating in the genomic rearrangements under stress factors of the remote hybridization, is discussed, the primary structure of a Bam HI fragment (999 bp long) of Hordeum vulgare DNA being the example.