DNA, one of the most famous molecules is 140-years-old. Its history has engaged three centuries of experiments, leading us to a point, where the Homo sapiens genome sequence is known. The "DNA breakthrough" is dated on 1953, when James Watson and Francis Crick proposed the model of molecular structure of DNA. But the origin of that great achievement goes back to 1869 and early efforts of Friedrich Miescher, the Swiss doctor, who isolated DNA (than termed nuclein) for the first time. Since that time wealth information on "nuclein", its functions, structure and usage has been collected and formed a basis for modern molecular biology, chemical biology and biotechnology. This article describes the events and circumstances of the most important DNA discoveries since its first isolation up to completing the human genome project and deep DNA sequencing techniques application.