Supplementary web page for the paper:

Pedro Carpena, José L. Oliver, Michael Hackenberg, Ana V. Coronado, Guillermo Barturen and Pedro Bernaola-Galván. 2011. High-level organization of isochores into gigantic superstructures in the human genome. Physical Review E 83: 031908 (1-7)

Human DNA shows a complex structure with compositional features at many scales; the isochores—long DNA segments (~10^5 bp) of relatively homogeneous guanine+cytosine (G+C) content—are the largest well-documented and well-analyzed compositional structures. However, we report here on the existence of a high-level compositional organization of isochores in the human genome. By using a segmentation algorithm incorporating the long-range correlations existing in human DNA, we find that every chromosome is composed of a few huge segments (~10^7 bp) of relatively homogeneous G+C content, which become the largest compositional organization of the genome. Finally, we show evidence of the biological relevance of these superstructures, pointing to a large-scale functional organization of the human genome.