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 M, generation of an experimental population of rye (Secale cereale L.) to its M-2 progeny. Although high frequencies of large structural rearrangements were detected in root-tip meristems of M-1 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.