Scientists: James Watson and Francis Crick
Hypothesis
Did the discovery of the molecular structure, of Deoxyribonucleic acid (DNA), aid biologists in understanding human evolution?
Introduction
James Watson and Francis Crick, two famous biologists, credit for the discovery of the molecular structure of DNA. Generally it is believed that James Watson and Francis Crick discovered DNA; however, it is not true. Long before they published their paper in Nature, regarding the structure of DNA, Friedrich Miescher, a Swiss physician, had isolated DNA; however, he was unable to study it in detail because of technological limitations (Noble Prize Organization, 2014).
Francis Crick and James Watson revealed the molecular structure of DNA, and in the paper they published, they discussed attributes of the molecular structure. For instance, they claimed, by physical evidence, that human DNA is a Double Helix structure and that the double pairing is responsible for the stability of DNA and precise copying of genes. In the paper, they discussed what could be the causes of Double-Helix structure and how this structure affects replication.
The discovery of molecular structure, of DNA, allowed scientists to understand evolution, of life (in general) and humans (in particular), better. With the discovery, of the molecular structure of Human DNA, scientists learned why the process of mutation is so gradual and subtle.
Method
For the discovery of molecular structure of DNA, James Watson and Francis Crick used different methods, such as x-rays, to establish that human DNA is double Helix. Also, they also suggested that the shape of DNA affects the replication process; makes it more precise.
Figure and Analysis
Figure
In this section of the study, we will provide a figure of Molecular Structure of DNA, and we will discuss how it is important.
Below is the picture of the original DNA model by James Watson and Francis Crick. It is quite apparent that the model provides rudimentary information regarding the molecular structure of DNA. For instance, the base-pairing in this model is not apparent, which is one of the important characteristics of DNA. Later models, which were more sophisticated, elaborated and complex, provided a more detailed understanding of pairing, which is important in understanding how DNA is a genetic code and how this genetic code is preserved and deciphered. For instance, this model does not explicitly reveal that there are rules of base pairing; adenine will pair with thymine and cytosine will pair with guanine. Also, it does not provide comprehensive information, explicit, regarding the proportion of these nuclei-bases or nucleotides (Brennan, 2017).
It is essential to understand that the formation of DNA has a method and a pattern. The understanding of the method or pattern allows us to understand how organisms evolved. The structure itself provides understanding regarding mutation and its pace. For instance, studies reveal that peculiar shape of DNA (Double Helix) eases the process of replication. As both the strands, of DNA, act as a regulator and also a template; therefore, its replication is more precise. Watson and Crick have also suggested that the shape of DNA facilitates replication.
The structure in the original figure does not look stable when the double helix DNA structure is very stable, which does not allow it to mutate rapidly. It explains why human evolution is slow and why the mutation occurs so subtly. Also, the model, which we can see in the picture, also does not provide any piece of information on RNA, which is more prone to mutation.
Analysis
It is evident from the study about the discovery of DNA that before Francis and James published their famous paper, the scientific community had a very vivid idea regarding DNA. Most of the scientists acknowledged it as a life-molecule; however, there was little information regarding its structure, which might have given its physical and chemical attributes.
To learn about the structure of DNA, James and Francis used Stick-and-Ball Model. This model was devised to conjecture possible molecular structures of DNA (testing of ideas). This technique was unusual for this endeavor, as most of the scientists were using experimental methods instead of Stick and Ball model. For instance, Rosalind Franklin Opted X-ray diffraction model are for understanding the physical structure of the DNA molecule.
Study of this subject reveals that final discovery, regarding the molecular structure of DNA, was based on borrowed/shared information. For instance, the x-ray picture of DNA, which had been crystallized under particular conditions (moist), allowed James and Francis to guess the helical structure of the molecule accurately. Similarly, important information regarding the base pairing, by Erwin Chargaff, facilitated James and Crick in measuring the size or length of DNA. Also, it also allowed them in understanding the smooth sugar-phosphate backbone of the DNA molecule that stemmed outwards. Therefore, we can say that the final discovery of the molecular structure of DNA was based on two different pieces of information. The understanding of pairing rules also helped in projecting/guessing the attributes of DNA (Watson & Crick, 1993). “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material”(Watson & Crick, 1993).
Conclusion
In the end, it is concluded that the finding of the molecular structure of DNA was enormous, as it allowed in understanding the origin and evolution of life. There are many scientists and scientific organizations, which are attempting to understand why DNA has that particular shape and what factors have contributed to its double-helix structure. Future studies should isolate factors that give physical and chemical characteristics of the DNA of living organisms. It will able us to construct a more authentic narrative regarding the origin and evolution of life.
References
Brennan, J. (2017, April 25). The Structural Stability of the DNA Double Helix. Retrieved from https://sciencing.com/structural-stability-dna-double-helix-2232.html
Noble Prize Organization. (2014). The Discovery of the Molecular Structure of DNA – The Double Helix. Retrieved from https://www.nobelprize.org/educational/medicine/dna_double_helix/readmore.html
Watson, J. D., & Crick, F. H. (1993). Genetic Implications of the Structure of Deoxyribonucleic Acid. The Journal of the American Medical Association, 269(15), 1967-1969.
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