Miller and skoog identified a chemical in old herring sperm DNA which is responsible for cell division in tabacco pith culture. They called it kinetin.The most active cytokinin was discovered by D.S. Leathem, which he named as Zeatin. After Leathem, it was identified by Miller. Both used the milky endosperm of corn as a source for stimulation of cell division in tissue culture. Zeatin has been identified in various parts of seed plants. Kinetin is not found in plants and also not formed by the plants. Zeatin is not a product of breakdown of DNA and it is also not present in the DNA.