Molecular biology, early days

The early history of the foundations of modem molecular biology has been recounted many times. In my view, the best source is H. F. Judson, The Eighth Day of Creation, Simon and Schuster, New York, 1979. 

DNA molecules are very large, and this size caused considerable problems in the early days of molecular biology. Understanding the precise function of particular stretches of DNA required isolating that part of the DNA molecule and then obtaining enough of it to work with. As Watson (2004) commented ... 

Paladini, A. C. 1995. The early days of the Institute de Investigations Bioquimicas, Fundacion Campomar. In Sucrose Metabolism, Biochemistry, Physiology, and Molecular Biology (H. Pontis, G. Salerno, and E. Echeverria, eds.), pp. 1-3. American Society of Plant Physiologists, Rockville, MD. 

Discovery of the structure of DNA in 1953 and subsequent elucidation of how DNA directs synthesis of RNA, which then directs assembly of proteins—the so-called central dogma—were monumental achievements marking the early days of molecular biology. However, the simplified representation of the central dogma as DNA—>RNA— protein does not reflect the role of proteins in the synthesis of nucleic acids. Moreover, as discussed in later chapters, proteins are largely responsible for regulating gene expression, the entire process whereby the information encoded in DNA is decoded into the proteins that characterize various cell types. 

Reflect and Apply In the early days of molecular biology, some researchers speculated that RNA, but not DNA, might have a branched rather than linear covalent structure. Why might this speculation have come about ... 

Despite the high power of the electron microscope, which achieves resolutions of the order of 3 A, i.e. molecular resolution, the reliability of the method has been questioned in the past. These doubts especially involve the possibility of electron-beam damage and the shortcomings of the preparation techniques. The latter involve chemical fixation, dehydration and staining which might interfere or even disturb the native structure. The development of adequate preparation methods is therefore of utmost importance for high resolution electron microscopy of biological specimens. This has been realized from the early days of electron microscopy. 

Structure of high-energy molecules. Chem. in Brit. 6 (1970) 468-472. [74-6] The molecular basis of biological specificity. Nature 248 (1974) 769-771. [86-15] Early days of molecular biology in the California Institute of Technology. Ann. Rev. Biophys. Chem. 15 (1986) 1-9. 

Figure 3. Some facts and open questions about the origin of life. The concept of an RN A world preceding present-day genetics based on DNA, RNAand protein, has been conceived by chemists and molecular biologists interested in problems of prebiotic chemistry and early biological evolution. Several pathways which are plausible under...

---