Abstract
For the first time, the growth rate of minimal animal genome size is shown to slow down in the course of evolution from prokaryotic forms to mammals after the Cambrian explosion. There is proposed an original mathematical model which takes into account a multiphase character of development and importance of multidirectional trends in the evolution. The authors explain from the biological point the exponential change of minimal genome size in the beginning of the evolutionary process, slowing down after the period of the Cambrian explosion as well as reveal certain parameters of the evolutionary processes as a result of the model application. According to the proposed model, theS-shaped curve with distinct inflexion point adequately describes the increase of minimal genome size.