Principal Component Analysis of Mouse Genomes Unravels Strong Genetic Robustness during Evolution - Special Issue

Genetic robustness may have a crucial role in speciation. Nevertheless, its mechanism is still under debate. We analyze by means of principal component analysis the genomic correlation of several mouse subspecies and discriminate between two distinct and mutually orthogonal processes of genetic differentiation which can be equated to interspecific and intersubspecific divergence. While the first principal component is responsible for the separation of different species, the second and third principal component discriminates between different strains within the same species. We find that the across genome correlation distance is both robust and highly different between the two components, and displays a scale invariant distribution. We also report a scale invariant, heterogeneous (non-stochastic) 7 ray clusters of the system variation that may be equated to the biological process. These findings suggest that the correlation structure of millions of genetic elements along the genome is highly important during the process of evolution and may indicate of strong constraints. Moreover, based on our results, we postulate that the observed genetic robustness can distinguish between micro- and macro-evolution, a phenomenology that was predicted by the punctuated equilibrium model and gain more profound view for the role of complex interacting networks on genome evolution.