A RANDOM-WALK GIANT-LOOP MODEL FOR INTERPHASE CHROMOSOMES

Fluorescence in situ hybridization data on distances between defined g enomic sequences are used to construct a quantitative model for the ov erall geometric structure of a human chromosome. We suggest that the l arge-scale geometry during the G(0)/G(1) part of the cell cycle may co nsist of flexible chromatin loops, averaging approximate to 3 million bp, with a random-walk backbone. A fully explicit, three-parametric po lymer model of this random-walk/giant-loop structure can account well for the data, More general models consistent with the data are briefly discussed.