Embryonic Development of Frogs Under ELF Magnetic or Electric Fields

The effect of extremely low frequency (ELF) magnetic and electric fields on the initial embryonic development of frogs was studied. The embryos were destroyed by a 20 Hz ac current applied directly to the embryos for eight hours in the cleavage-blastula stage as the current density exceeded 100 ¿A/mm². When applied to the embryos in the cleavage-blastra stage, embryo development was disturbed when mRNA synthesis began, and subsequently embryo development was generally abnormal. Thus, electromagnetic fields exert a powerful influence on embryo development in the latter half of the cleavage stage.