Ethanol induced notochord and spinal cord duplications in the embryo of the zebrafish, Brachydanio rerio



Embryos of Brachydanio rerio, stage 10 (Hisaoka and Battle, '58) were exposed for 24 hours to graded concentrations of ethanol from 1 to 3%. Developmental abnormalities included defects of the eye, i.e., approximation, confluence and fusion of the optic cups mid-ventrally; as well as duplications of notochord and spinal cord. Duplication of the spinal cord in the hind brain region has not been reported previously. The duplicatory effects are discussed and a mechanism of duplication by infolding roof plate material is proposed.