Oswald T. Avery and the Discovery of the DNA

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Table of Contents

Introduction
Background
Serendipity and Hard work
Significance of Discovery
Conclusion
Works Cited

Introduction

It was not Oswald Avery’s main goal to discover the material that controls the expression of genes in biological organisms. He was working on something else when he and his team realized that it is the Deoxyribonucleic acid or DNA that is dictates the expression of biological characteristics from something as complex as eye color to the more simple such as the determination of which type of protective coat a bacterium will develop to defend itself. It was groundbreaking discovery indeed. But it took decades before Oswald Avery and his team received the recognition that they so well-deserved. It was partly due to the humble demeanor and cautious ways of Avery that made their work go unnoticed for a very long time. It can also be partially attributed to the science behind genetics; its complexity made it difficult for others to truly appreciate what Avery and his team has accomplished in 1944. Oswald Avery was a man driven with the desire to contribute to humanity but when he finally discovered something of utmost importance the world of science was not quick enough to give recognition to his work.

Background

Oswald Theodor Avery was born on October 21, 1877. That piece of information will help provide a little perspective on his background. He was born before two decades before the 20^th century, at a time when the whole world is still struggling to understand microorganisms and other aspects of biology that could not be observed by the naked eye. Oswald Avery was born to English parents. His father Joseph Francis Avery was a Baptist pastor and his mother, Elizabeth Crowdy was also religious and active in ministry (Simmons, 113). The family first immigrated to Halifax, Nova Scotia before they decided to relocate to New York.

Moving to New York was beneficial to the career of his father because he became the pastor of the Mariner’s Temple which still stands today on Lower East Side Manhattan (Simmons, 113). But this move also benefited Oswald because he was able to study medicine at the Columbia University College of Physicians and Surgeons and finally received his medical degree in 1904. After college he became interested in research and went to work at the Hoagland Laboratory in Brooklyn. It is at this time when Oswald Avery established the pattern of his career which was described by his biographer as the, “…systematic effort to understand the biological activities of pathogenic bacteria through a knowledge of their chemical composition” (Dochez, par. 3). It is also at this time when he was noticed by Rufos Cole director of the hospital of the Rockefeller Institute. At his prodding he was able make Oswald Avery leave Hoagland Laboratory and transfer to the Rockefeller Institute.

By the turn of the 20^th century it was clear that Avery would use his exceptional intelligence and capacity for hard work to find solutions to problems that plague mankind. In 1913 he decided to come and work in the Rockefeller Institute for Medical Research. At that time it was one of the most prestigious places to work with if one considers himself a scientist or researcher. It was the sort of place where Avery can easily fit in. The said institute was founded in 1901 by John D. Rockefeller. The Rockefeller Institute was established at time when infectious diseases such as tuberculosis, diphtheria, and typhoid fever were the greatest threat to human health (The Rockefeller University, par. 4). Thus, the institute became the first biomedical research center in the United States.

When Avery came to Rockefeller he was not hunting for DNA, the genetic material but he was more interested about harmful bacteria. In fact, “…he came to study differences in virulence among strains of pneumococcus, a bacterium that causes severe pneumonia” (The Rockefeller University, par. 8). It is his study on pneumococcus that led him to discover that DNA has something to do with heredity. But it was not going to be smooth travel all the way. Avery and his team were very cautious with regards to this discovery and this may have been the major contributing factor why it took a long time before the scientific community gave them the recognition that they richly deserved.

Serendipity and Hard work

It seems that there are many discoveries in the biomedical field that came as the byproduct of a series of serendipitous events. The story regarding the serendipitous discovery of pasteurization is well-known in the scientific community. The same is true with the discovery of DNA as the hereditary material. Oswald Avery, Colin Mcleod and Maclyn McCarty set their sights on understanding infectious diseases but their hard work was rewarded with the discovery of DNA. But it has to be pointed out that without the previous research made in the field of genetics it would not have been possible for the trio to realize that they have stumbled upon something significant.

Avery, Mcleod and McCarty were standing on the shoulders of great scientists who came before them, especially those who contributed much to the advancement of genetics which at that time was a new science that tried to explain biological hereditary phenomena. It was Mendel who started it all when in 1865 he published his work concerning the hereditary factors that made it possible for parents to influence the physical attributes of their offspring. Decades later it was Johannsen who coined the term “genes” to describe the so-called hereditary factors first described by Mendel. Then in 1906 Bateson defined genetics as the, “…science that studies inheritance and variation in living beings” (Lacadena, 3). But in 1944 Avery, Mcleod and McCarty did not wish to add to the rapid development of genetics they were simply trying to use the principles gleaned from past discoveries to help them in their quest to stop pneumonia.

Avery and his team worked hard to gain a better understanding of the bacteria that causes acute infection of the alveolar spaces in the lungs that in turn would cause severe pulmonary congestion. Louis Pasteur was the first one to isolate the fist strain of pneumococcal bacteria in 1881 (Simmons, 114). From then on other scientists were able to identify other pneumonia-causing bacteria. Avery and his team at the Rockefeller Institute took great pains in “…typing the various strains of pneumococci … which were distinguished by shape and other significant characteristics…” (Simmons, 114). Avery and his team knew very well that differences in biological characteristics in different pneumococcal bacteria is the reason why some are deadly while others are relatively harmless.

Avery discovered that lethal types of pneumococcal bacteria are encapsulated and this is the reason why white blood cells could not neutralize them. White blood cells, the major component in the body’s immune system normally engulf pathogens, thus protecting the body from their deadly effects. But the capsule makes it impossible for the immune system to do its work. Avery continued to study different strains of pneumonia causing bacteria until another scientist made a breakthrough that would set a chain reaction of events.

While Avery and his colleagues were content in tracking down the development of pneumococcal bacteria the scientific community was stunned by the discovery of a British researcher named Frederick Griffith. By chance, Griffith found out that by injecting dead but lethal bacteria into mice together with harmless and yet living bacteria the mice developed pneumonia (Simmons, 114). Scientists all over the world had the right to be amazed and at the same time skeptical. Griffith’s experiment seems to indicate that life comes from non-living matter. This theory has been debunked a long time ago. Life only comes from life and so Avery and his team decided to recreate Griffith’s experiment in order to prove him wrong.

Avery, Mcleod and McCarty were able to replicate Griffith’s research methodology but they were surprised by what they learned in the process. When Griffith was asked as to the explanation for this phenomenon he said, “…the dead bacteria might furnish some nutrient to the living bacteria by which they developed a capsule and became lethal” (Simmons, 115). It was an interesting theory but Avery and his team was able to prove that this is not the answer.

In 1931 Avery and his colleagues were able to make the first breakthrough. They discovered that the mice used in Griffith’s experiment could be discarded because even if they would place dead virulent bacteria and live harmless bacteria in a Petri dish the same thing occurred. According to Simmons (115), Avery had one burning question that he needed an answer: What is the substance responsible? From that day forward his team was no a mission to isolate and purify until they will be able to identify the agent that caused the transformation.

The following will help summarize the methodology used by Avery, Mcleod and McCarty:

Beginning with some 20 gallons of bacteria, Avery and his colleagues employed centrifuges, filters, and chemical reagents in attempts to isolate the substance … Avery and his colleagues attempted to disable the transforming mechanism in pneumococci by removing protein, they failed. When enzymes that attacked DNA were used, the principle became inactive. Separated by centrifuge, the “transforming principle” proved to be a homogenous substance that could be matched to DNA (Simmons, 115).

Instead of celebrating, Avery and his team could not see the significance of their discovery. They were the pioneers and there is not enough prior research made that could back up their claim or could even encourage them that they are on the right track. This led many to conclude that in the aftermath of the discovery, “Avery et al. were overcautious and extremely skeptical” (Hausmann, 103). They could not be blamed for feeling that way because what they were able to accomplish was truly a groundbreaking discovery. They were trailblazers who could not see very far ahead.

Significance of Discovery

The discovery that the DNA was responsible for heredity was able to establish genetics as a new science that will now be able to explain why parents pass on their characteristics to their children. According to one author the discovery was able to finally answer the second question pertaining to the early beginnings of genetics and these two questions are listed as follows (Lacadena, 3):

What are the laws by which biological characters are transmitted from parents to offspring?
What is the physical basis by which such characteristics are conserved and transmitted?

Gregor Mendel was able to answer the first question and then Avery, Mcleod and McCarty were able to answer the second one in 1944. Logic therefore dictates that these men should have been rewarded for their efforts or at least be celebrated in the scientific community for their highly intelligent work and groundbreaking discovery. But there was no Nobel Prize for them. In fact when one mentions DNA the first name that comes to mind are the two Nobel laureates named Watson and Crick who were able to show that DNA is a double-helix structure. But it is doubtful if Watson and Crick would have pursued their study without the findings of Avery, Mcleod and McCarty.

There were other factors involved as to why their work were not recognized in their lifetime or even shortly afterwards. First of all Avery was already 67 years old by the time he published his now famous work (Hausmann, 109). He died shortly after the publication of his work regarding DNA. Secondly, Avery and his team were overly cautious. The following statement is the only statement that they permitted themselves to reveal to the whole world. After the experiments they declared, “The evidence presented supports the belief that a nucleic acid of the deoxyribose type is the fundamental unit of the transforming principle of Pneumococcus Type III” (Hausmann, 109). It was very clear that they tried to limit their conclusions on the experiments that they previously conducted and they did not permit their imagination to wander beyond that.

If they permitted themselves to publicly express what they felt in private regarding the DNA as the genetic material then the world would have noticed and it would invite more scrutiny and because Avery, Mcleod and McCarty were very thorough then the world will know that they were correct in their assertion. But they never made that assertion. On the other hand there could be a third factor why the three men were not as famous as Watson and Crick. At the time of the discovery in 1944 very little was known about genetics and DNA, the world was not yet ready for such experimental results. It would take some time before the world would take notice.

Conclusion

Avery was the son of religious parents. This fact coupled with his other life experience made him a compassionate man ready and willing to help those who are in need. His skills, talent, and immense intellect were put to good use when he studied medicine. It was plain to see that he will use his expertise in helping people through healthcare. It did not take long after graduation from Columbia University that he soon discovered he was meant to be a researcher. His great work ethic and his dedication to his job earned him a spot at the prestigious Rockefeller Institute for Biomedical Research and it is here where he devoted his life to fighting infectious disease.

But while working in the institute, Avery, Mcleod and McCarty were forced to veer a little bit in their quest to find a cure for pneumonia. They were forced to investigate the validity of Griffith’s experiment because he claimed that dead virulent bacteria when injected into mice with live harmless bacteria the mice died from pneumonia. It was the need to prove Griffith wrong that led Avery and his team to the discovery that the transforming factor is the DNA. This discovery firmly established the fact that DNA is responsible not only in transforming harmless bacteria into lethal ones but it also proves that DNA is the physical basis for passing characteristics from parents to offspring.

While they were still alive their contribution to the world of genetics was never properly recognized. Others with similar groundbreaking discoveries were able to receive a Nobel Prize but not Avery, Mcleod and McCarty. Part of their problem is that they were overcautious. No one could blame them because they were treading into uncharted territory. Moreover, at the time of publication only a few people fully understood hereditary laws as well as DNA. But in the 21^st century they are now enjoying the recognition that they so richly deserved.

Works Cited

Dochez, Alphonse. “The Oswald T. Avery Collection.” Profiles in Science: National Library of Medicine. 2008. Web.

Hausmann, Rudolph. To Grasp the Essence of Life. MA: Kluwer Academic Publishers, 2002.

Lacadena, J.R. “Cytogenetics: Yesterday, today and forever. A conceptual and historical overview.” Chromosomes Today. Eds. Henriques-Gil, N., J.S. Parker, & M. J. Puertas. New York: Springer, 1997, 3-10.

Simmons, John. Doctors and Discoveries. MA: Houghton Mifflin Company, 2002.

The Rockefeller University. “More than a century of science for the benefit of humanity.” 2008. Web.

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