Aneuploidy and genome organization in sperm nuclei of cattle and river buffalo detected by fluorescence in situ hybridization (FISH) and chromosome microdissection

New technologies in molecular cytogenetics have remarkably facilitated the visualization of whole chromosomes or subchromosomal regions in interphase nuclei. Consequently, both somatic and sperm nuclei have been under investigation, in order to study the territorial organization of genetically ‘active’ versus ‘inactive’ genomes. Purpose of the present study was to investigate whether in river buffalo sperm nuclei, chromosomes X-, Y- and 5p (corresponding to chromosome 29 in cattle) maintain or change their relative position compared to cattle. Furthermore, since chromosome organization in the nucleus could affect meiotic segregation, we decided to study X-Y chromosome segregation in river buffalo sperm and developed a dual colour FISH method for evaluating the baseline level of aneuploidy in spermatozoa of this species, that could be used as reference for further investigations on the genotoxic effects of environmental mutagens and bio-hazards directly on the germ-cell line.