Abstract
Recent completion of the human genome sequence is a spectacular achievement of the 20th-century biology. This achievement has opened the door for future revolutions in biological and medical sciences. By learning about the gene sequences and the individual genetic differences, scientists hope to understand the molecular basis of the normal state and the diseased state of life on one hand, and individualize medicine on the other hand. However, the human genome sequencing project was not an isolated, spectacular undertaking. Rather, it was a natural extension and the culmination of the advances in the science and techniques of molecular biology. The present article is an attempt to summarize these major landmarks in the history of DNA research, beginning from the identification of “nuclein.”