[The stem cells of animal tissues].

A brief historical review of concepts on stem cells is given with a stress made on the role of Russian scientists A. A. Maksimov and A. A. Zavarzin who have formulated key problems in biology of stem cells and cell renewal. Principal stages in current studies of stem cells are considered. An outline is given of traditional and recent trends in the investigations: comparative studies of tissue systems with stem cells; molecular genetic mechanisms of the self-maintainance and the differentiation of stem cells; stem cells as a subject of gene engineering.