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.