Erwin Chargaff (born in 1905 in Chernivtsi) determined the quantitative relations of nitrogen bases that are part of nucleic acids. The scientist explained his discovery in the “Chargaff’s Rule”, namely the overall number of adenine surplus in every molecule in the DNA equals to the thymine surplus. By the same token, the number of guanine surplus equals to that of cytosine. Chargaff’s Rule played a decisive role in de-ciphering the DNA structure in a shape of double helix by James Watson and Francis Crick. Chargaff’s studies laid the foundations for a rapid development of genetics research.