David Yaffe's study investigates the retention of differentiation potentialities in myogenic cells during prolonged cultivation. The research focuses on whether the capacity of myoblasts to fuse and differentiate into multinucleated muscle fibers can be maintained over extended periods of in vitro multiplication. Using primary skeletal muscle cultures from newborn rats, Yaffe developed a method to maintain myogenic cell lines for months without losing their differentiation potential. This was achieved by promoting cell multiplication, preventing cell fusion, and selecting myoblasts from the heterogeneous population in primary cultures. The study demonstrates that myogenic cells can be maintained through serial passages, and their differentiation potential is inherited by nearly all progeny cells. The results suggest that the ability to transmit differentiation potentialities is maintained within the stem cells themselves, without interaction with other cell types, and that this mechanism allows for continuous reproduction of the differentiated state. The findings have implications for understanding the regulation of cellular differentiation and the potential for using myogenic cell lines in various biological and medical applications.David Yaffe's study investigates the retention of differentiation potentialities in myogenic cells during prolonged cultivation. The research focuses on whether the capacity of myoblasts to fuse and differentiate into multinucleated muscle fibers can be maintained over extended periods of in vitro multiplication. Using primary skeletal muscle cultures from newborn rats, Yaffe developed a method to maintain myogenic cell lines for months without losing their differentiation potential. This was achieved by promoting cell multiplication, preventing cell fusion, and selecting myoblasts from the heterogeneous population in primary cultures. The study demonstrates that myogenic cells can be maintained through serial passages, and their differentiation potential is inherited by nearly all progeny cells. The results suggest that the ability to transmit differentiation potentialities is maintained within the stem cells themselves, without interaction with other cell types, and that this mechanism allows for continuous reproduction of the differentiated state. The findings have implications for understanding the regulation of cellular differentiation and the potential for using myogenic cell lines in various biological and medical applications.