Fractal properties of the human genome

The fractal dimension of the human chromosomes and four other genomes were determined using the box counting method. Human chromosomes exhibited a fractal dimension (D) of about 0.8, while values for a bacteria, yeast, worm and plant were higher. Analysis of three human chromosomes over five orders of magnitude of scale (from 108 to 104 bp), showed D to be non-constant at the smaller scales, when introns were included as gaps. The relationship between D and gene density fit an empirical equation related to that expected from theory, and allowed for the calculation of the fractal initiator or self-similarity ratio. This value (0.57) was constant at all scales for human chromosomes, and was similar for other species, except for Arabidopsis.