Correlated positioning of homologous chromosomes in daughter fibroblast cells.

A new method of analyzing chromosome segregation in pairs of daughter human fibroblasts revealed that the positioning of chromosomes in daughter nuclei was closely correlated with their relative positions during the G1 interphase. Two topographic values, namely distance and the angular separation between a pair of homologous chromosomes, were determined using fluorescence in-situ hybridization with four different centromeric DNA probes. These topographical values exhibited a broad distribution as a population, but, to our surprise, both were strongly correlated within each pair of cells derived from the same mother cell (daughters). This correlation was not affected by cell-to-cell distances between daughter cells. We demonstrate in this report that the positioning of chromosomes at G1 interphase is chiefly determined by their configuration at mitosis, consistent with the nuclear architecture model in which chromosomes are immobile at a global scale in the G1 interphase nuclei.