Distribution of [³H]thymidine in the lens of the rhesus monkey (Macaca mulatta) embryo

Tritiated thymidine autoradiography was conducted on early developmental stages of the lens in the rhesus monkey (Macaca mulatta) embryo. Embryos ranging in age from stage 13 through stage 20 were labeled for 1 hr with 100 μCi [³H]thymidine. The labeling index was the highest in the lens placode stage and then dropped markedly during invagination of the lens. Most cells in the deep wall of the lens vesicle lost the ability to incorporate [³H]thymidine prior to closure of the lens pore. The superficial wall continued to exhibit labeled nuclei and maintained a stable labeling index from stages 16 through 20. Comparisons were made with autoradiographic data available for the chick and rodent lens.