Before revision:  The numerical efficiency of our method allows for the analysis of entire genomes and of random sequences of corresponding length (10^6-10^9 bp). At physiological temperatures and superhelical densities, opening is strongly cooperative with average bubble sizes of  O (100-1000) bp.
After revision:  The numerical efficiency of our method allows for the analysis of entire genomes and of random sequences of corresponding length (10^6-10^9 base pairs). We show that, at physiological conditions, opening in superhelical DNA is strongly cooperative with average bubble sizes of  O (100-1000) bp.