[Presumed role of the gravity in the establishment of the symmetrization in amphibian embryos. Response provided by the biological experimentation in space].

During the early embryonic development of the amphibian, several events are presumed to be dependent on the ground gravity (egg rotation of equilibrium, formation of the grey crescent, symmetrization, cleavage). Will development occur normally in the absence of the gravity? The experience FERTILE had led to obtain in weightlessness, onboard the space station Mir, the natural fertilization and the embryonic development of the salamander Pleurodeles waltl, an amphibian urodele. All the embryos developed in microgravity acquired normal bilateral symmetry.

Effects of space environment on embryonic growth up to hatching of salamander eggs fertilized and developed during orbital flights.

In vertebrates, only few experiments have been performed in microgravity to study the embryonic development from fertilization. To date, these concern only amphibian and fish. We report here a study on the embryonic development of Pleurodeles waltl (urodele amphibian) eggs oviposited in microgravity.