title: DNase I hypersensitive sites along the XY bivalent at meiosis in man include the XpYp pairing region.
abstract: The DNase I nick translation technique has been applied to human meiotic chromosomes in situ. At metaphase I, distinct hot spots of autoradiographic labelling occur at three positions along the XY bivalent; over the Xpter and Ypter pairing tips, over Xq and Yq terminal/telomeric segments, and at a site just below the centromere in Xq. The latter might correspond to the postulated human inactivation centre. Compared with somatic chromosomes, human meiotic bivalents in general exhibit a greater accessibility to DNase I. Site-specific conformational changes in the DNA between somatic and germ line cells could be a necessary prerequisite for crossing-over.
mesh_terms: D001345:Autoradiography; D004261:DNA Replication; D003850:Deoxyribonuclease I; D006801:Humans; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D003850:Deoxyribonuclease I