Nodal signals are required in early embryonic development to pattern left-right asymmetry, to develop germ layers, especially mesoderm and ectoderm, and to develop the nervous system of vertebrates. This research studied on the temperature sensitivity of the one-eyed pinhead connected to squint (sqt) and cyclop (cyc) in TGFβ super signaling pathway. Half embryos from each batch of oepm134 mutants were incubated in either 28.5̊C or 34̊C. The penetrance of oepm134 was analyzed by staining pineal glands through in-situ hybridization. Higher percent of elongated and divided neural tubes was found in embryos incubated in 34̊C than that in 28.5̊C. The hypothesis was supported that the penetrance of oepm134 gene expression was temperature dependent.