To demonstrate the phenomenon of homologous inhibition by clearly interpretable results in a readily reactive system, experiments were carried out to study the effect of chick whole eye extract on the development of the vesicular lens of the chick embryo in vitro. The heads of embryos of 11 through 13 somites were explanted onto nutrient medium diluted with varying amounts of the extract, and cultured for 30 hours. A total of 35 embryos exposed to concentrations of 1:1, 1:2, and 1:4 (extract to medium) showed complete inhibition of lens vesicle formation. Of a total of 53 embryos on concentrations of 1:8, 1:16, 1:32, and 1:64, more than 50% showed inhibition of vesicle formation. The inhibitory effect disappeared at a concentration of 1:128. Control material exposed to some equivalent concentrations of nutrient medium – saline mixtures showed inhibition of vesicle formation in only 15% of 33 embryos. Of a total of 27 control embryos exposed to ventricular muscle extract, approximately one-third showed inhibition of vesicle formation at concentrations of 1:8 and 1:16, with the inhibitory effect disappearing at 1:32. The implications of this result are discussed. Other factors and control experiments are described and their value is assessed.
Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia
