Fig. 5.

A hypothetical evolution of the fourth and fifth CREF eigen-modules from the apes to humans. In the ape genomes, the distances between the fourth and fifth singular values are statistically significant, therefore, their corresponding eigenvectors are orthogonal to each other. Along the evolution, the two singular values approached, likely driven by the mutations related to Alu elements together with other mechanisms. At one point, the two levels became identical and consequently the two 1D eigenvectors fused into a 2D eigen-space, in which any direction was an eigenvector. This 2D eigen-space formed a space of the CREF-polymorphisms. Then selection could occur. In comparison to the fourth and fifth motif eigenvectors of the chimpanzee, the human’s ones were rotated 28.4°. We compare the deviance of the distance between the fourth and fifth levels in each species from that generated at its fusion point. The results support that the distances to the fusion point is increasing in the order of humans, chimpanzees, and orangutans.