Yasuo Kawamoto

Mitotic Activity in the Inbred and Hybrid Quail Embryos

In the previous papers5), marked retardation in embryonic development and decrease in embryonic weight were found in the inbred lines, while restoration of embryonic development and embryonic weight was observed in crosses between inbred lines of Japanese quail. It is well known 2-4,10) that cell number increases during morphogenesis of the early chick embryos and that a highly positive correlation is found between the early embryonic development and cell number. Furthermore, mitotic activity such as the number of mitotic cells and mitotic index 4,8,11) is used as an indication of cell increase in relation to the rate of embryonic development. However, there is very little published information on the relationship between embryonic development and mitotic activity of quail embryos. This study was undertaken to investigate the mitotic activity in the inbred and hybrid quail embryos. Materials and Methods The Japanese quail used in this study consisted of inbred lines (F=59.4%), crossbreds obtained by crossing between inbred lines (F= 50.0%) and a randombred population as described in our previous report5). The number of pair-matings used in the inbred lines, crossbreds and in randombred population were 38, 34 and 40, respectively. The quail were kept under 14 hours light per day and fed freely with a diet containing 24% protein. The eggs for this study were collected and incubated for 48 hours at 38.2°C. At the