The common origin of symmetry and structure in genetic sequences

Giampaolo Cristadoro
Università di Milano-Bicocca


When exploring statistical properties of genetic sequences two main features stand out: the existence of non-random structures at various scales (e.g., long-range correlations) and the presence of symmetries (e.g., Chargaff parity rules). In the last decades, numerous studies investigated the origin and significance of each of these features separately. Here we show that both symmetry and structure have to be considered as the outcome of the same biological processes, whose cumulative effect can be quantitatively measured on extant genomes. We present a novel analysis (based on a minimal model) that not only explains and reproduces previous observations but also predicts the existence of a nested hierarchy of symmetries emerging at different structural scales. Our genome-wide analysis of H. sapiens confirms the theoretical predictions.