PAX6 expression pattern during lens development in the Iberian mole. PAX6 is expressed during the whole development of the mole lens. PAX6 protein is detected in both the head ectoderm of the presumptive lens and the optic vesicle at the s3 stage, as well as in the optic cup and invaginating lens placode at the next stage (s4a). From the onset of primary lens fibre differentiation (s4c) until adulthood, PAX6 is expressed in all the cells forming the lens, including both the anterior epithelial cells and nucleated lens fibres. Scale bar represents 200 μm in s10, s12 and s14 figures, and 100 μm in all the rest.