Distribution of 5-methylcytosine-rich regions in the metaphase chromosomes of Vicia faba.

The DNA methylation pattern of Vicia faba metaphase chromosomes was examined with a specific monoclonal antibody. 5-methylcytosine (5-mC) residues are present in different chromosomal sites, and are particularly abundant in telomeric and/or subtelomeric regions and in certain intercalary bands. Chromosomal localization of methylated regions enables a better knowledge of the lengthwise differentiation of this chromosome complement. Our results also indicate that there may be differences in monoclonal antibody binding between corresponding regions of homologous chromosomes in V. faba. This behaviour is detectable in specific regions with different frequencies. The data support results previously obtained for Allium cepa metaphase chromosomes using the same monoclonal antibody.