An intrinsic temporal dimension of DNA: the new concept of time-island

Abstract

In this article, we investigate the propagation of an intrinsic (not environmental) perturbation along the DNA chain. In particular, the conditions were sought so that a perturbation, in addition to moving in a coherent and complete manner, remained enclosed within a DNA fragment for a life time similar to those of biological interest of hundreds of picoseconds or in the time scale of nanoseconds. The conditions of closure of these pieces of DNA and the conditions of prolongation of the life time of the perturbation have allowed us to introduce the concept of time-island for the base-pairs sequences with these characteristics. The amount of such time-islands in human chromosomes and their coding parts has been calculated, and their uneven distribution has been highlighted. Finally, we study pieces of DNA made up of numerous replicas, as in the Huntington's disease. These systems with a number of replicas of the tens of units are, in fact, time-islands, albeit different from the simple ones already studied. By increasing the number of replicas, however, these time-islands tend to disappear because the coherence of the movement of the perturbation within them is lost. In this perspective, Huntington's disease, and other similar diseases, could be interpreted as the loss of a time-island.