THE QUAIL EMBRYONIC-DEVELOPMENT UNDER THE CONDITIONS OF WEIGHTLESSNESS

The experiment on board the orbital station,,MIR'' showed that normal development of quail embryos is possible and viable progeny can be obt ained although at a considerably smaller hatching rate and a higher fr equency of anomalies in the development of eyes, brain and beak. The m orphological indices of embryos and hatchlings did not show any notice able deviations in mass, and body size. An assumption was put forward concerning the possible secondary mechanism for development of these d eviations and a decreased hatching rate. Numerous authors have success fully studied different phases of embryogenesis of amphibians, fish, i nsects, birds and mammals in the course of several spaceflights. The f ull cycle of embryogenesis in weightlessness has not been studied as y et except for experiments with Drosophylla carried out by G. P. Parfen ov focused on genetics of gene rations of flies grown in space (Parfen ov 1988). Unfortunately, these experiments have not been recognized in literature as the first embryological experiments using insects and c overing the whole embryogenesis beginning with the moment of fertiliza tion in weightlessness. The study of embryonic development of birds du ring space flight is especially important as this model enables invest igation of the biological role of gravity as a general biology problem with its practical aspects, taking into consideration the fact that t he quail is a potential component of a life-support system of man in l ong-time space flights. The first, though not full, realization of thi s idea took place in 1979 on board the Soviet satellite ''Cosmos-1129' '. The work was carried out together with specialists from CSFR. A 12- days-long experiment yielded results on quail egg incubation under the conditions of weightlessness and showed that normal development of ab out 33 % embryos during 2/3 of their embryogenesis is possible, which was determined by the period of existence of the biosputnik. It was po ssible to work out technology for an experiment embracing the whole em bryogenesis and initial phases of post-embryonic development. The expe riment was carried out in 1991 on board the orbital station ''MIR''.