DNA molecules define the instruction set and control logic that allows cells to perform complex functions. Physically, these key constituents of life form remarkably long 3 meters fibers that must be packaged into 10 micron cell nuclei while regulating continuous access to essential genetic material.
Computational biologists at the Weizmann Institute developed models and algorithms to determine how such packaging is made possible amidst the stochastic and noisy processes that drive function within cells. DNA packaging into chromosomes was shown by the researchers to be organized hierarchically by loops. Large-scale loops divide each chromosome into well-insulated domains, containing only a few genes each. Smaller scale loops put each gene at the center of a powerful network of interacting genetic elements that facilitate sophisticated control. This design provides the genome with modularity, scalability and robustness to noise.
Topological analysis of genetic information is deeply influencing modern biology. For example, genetic variation in individuals can now be linked to genes causing potential disease based on topological relatedness, and not only genetic distance. On the other hand, chromosomal aberrations in cancer can be characterized based on their topological impact, leading to much improved understanding of the origins of the disease.