| Popis: |
According to up-to-date literature, one of the approaches to elucidating the essence of evolutionary events consists in admitting the importance of events which change genome activity. A crucial way of reorganization of gene activity is the inhetrited activation or inactivation of the genes. "Dormant" gene hypothesis and related data are reviewed in this connection. Most attention is concentrated on the study of inheritance and penetrance of fused gene in mice. By means of individual genetic analysis, it became possible to make a clear-cut distinction between the phenomenon of the lowered gene penetrance and its inherited inactivation. It was shown that low penetrance is a more frequent event which seems to mask the inherited inactivation of the gene. A general scheme of the phenomena studied is proposed. The classical conceptions claiming the existence of a reserve of hereditary variability concern mainly the recessive and codominant mutations. However, the role of dominant and semidominant mutations in the course of functional reconstruction of species may be important. During animal domestication, for example, everyone can see a lot of dominantly inherited characters appearing de novo. D.K. Belyaev's conception about "dormant" gene reserve is of great importance in this connection. Opening of the reserve at a particular evolutionary stage may drastically increase the genetic variability and lead to appearance of evolutionary novelty. |
