1. In 1852 a German scientist, Robert Remak published his observations on cell division and stated that the binary fission of cells was the means of reproduction of animal cells. 

2. This view was widely publicized by Rudolf Virchow who gave the phrase “Omnis cellulade cellula” means all cells arising from pre existing cells. 

3. In 1879 Walther Flemming reported that there were string like structures in the nucleus which split longitudinally during cell division. He named the process as mitosis means fine threads as the dividing structures resembled threads.

4. Wilhelm Roux proposed that each chromosome carried a different set of heritable elements and suggested that the longitudinal splitting observed by Flemming ensured the equal division of these elements. 

5. Combined with the rediscovery of Gregor Mendel’s 1866 paper on heritable elements in peas, these results highlighted the central role of the chromosomes in carrying heritable material or genetic material. 

6. The scheme of mitotic division was confirmed in 1904 by Theodor Boveri. 

7. The chemical nature of the genetic material was determined in a series of experiments over the next fifty years. 

8. The structure of DNA – the constituent of the genetic material was determined in 1953 by James Watson and Francis Crick.