The nature and destiny of translocated B-chromosome-specific satellite DNA of rye.

Translocations of A chromosome-specific and B chromosome-specific satellite DNA were tracked by fluorescence in situ hybridisation from an irradiated M1 generation of an experimental population of rye (Secale cereale L.) to its M2 progeny. Although high frequencies of large structural rearrangements were detected in root-tip meristems of M1 plants, none was present at meiosis or in somatic cells of their progeny. These results are interpreted in terms of efficient "filtering" of translocations during vegetative development, and not in the more usual terms of meiosis presenting a physical barrier to structural variants. These observations highlight the fact that B-A translocations are not tolerated, and may explain why this form of chromosome mutation is largely absent from natural populations.