Our understanding of genetic material has substantially increased since Friederich Miescher first extracted DNA in 1869. He discovered that a material exists within cells that precipitates out of acidic solution and dissolves into alkaline solution. He called it nuclein because it seemed to be located within the nucleus. It took until 1953 for the structure of DNA to be elucidated. It was during this time that procedures to isolate DNA began to emerge. Later, during the 1960's and 70's scientists were furiously untangling the cellular environment, and the discovery of RNA with its various forms and functions further refined DNA purification procedures. It was no longer enough to simply separate DNA from protein and salt impurities; it became necessary to remove contaminating RNA as well. Concurrently, scientists became interested in purifying messenger RNA (mRNA). Soon it became essential to purify not only DNA (genomic or plasmid), but also RNA in its various forms.