DNA methylation and chromosomal rearrangements in reconstructed karyotypes of Hordeum vulgare L.

One standard and two reconstructed barley karyotypes were used to study the influence of chromosomal rearrangements on the distribution pattern of DNA methylation detectable at the chromosome level. Data obtained were also compared with Giemsa N-bands and high gene density regions that had been previously described. The effect of chromosomal reconstruction in barley seems to be decidedly prominent in the repositioning of genomic DNA methylation along metaphase chromosomes. In comparison to the standard karyotype, the DNA methylation pattern was found to vary not only in the reconstructed chromosomes but also in the other chromosomes of the complements not subjected to structural alterations. Moreover, differences may occur between corresponding regions of homologues. Some specific chromosomal bands, including the nucleolus-organizing regions, showed a relative constancy in the methylation pattern, but this was not the case when the two satellites were combined by translocation in chromosome 6H(5H) of line T-30. Our results suggest that epigenetic changes like DNA methylation may play an important role in the overall genome reorganization following chromosome reconstruction.