In the view of molecular biology on morphogeny of a three-dimensinal embryo, morphogenesis and development are dependent upon activation of transcription of involving genes followed by the inactivation in a specific part of embryo at a certain time. It has been demonstrated that cis-acting elements of genes can act to provide sharply defined patterns. Simultaneously, it is accepted as an important mechanism that both activation and repression of transcription factors are closely related to cell differentiation and morphogenesis.