摘要
Development and evolution are two fundamental activities of life. In 1866 Ernst Hackell published the fundamental law of organ evolution, i. e. ontogeny is a recapitulation of phylogeny. So far, little progress has been achieved in the elucidation of its mechanism, particularly at molecular level. In mammalian tissues, the regulatory mechanism of cellular proliferation and differentiation of blood forming system has been studied in detail, and the regulatory
