Milestones in the History of Genetics

Written and compiled by: Louise Jan M. Lopez (Replichore)

(Photo courtesy of: www.tpr.org)

In the field of Genetics, there have been countless discoveries that expanded our understanding of all life forms. At the moment, Genetics has become one of the most widely understood science and has much attained all kinds of admiration and approval from the scientific community. It has become most successful in terms of its applications to the real world and on the innovations for the improvement of life.

Such discoveries are all equal in importance and has all contributed much for the realization of Genetics. But it is also critical to mention that there are some which seemed to be essential for its notable nature. In order to stress how such discoveries are indispensable in Genetics, the GENEWS Team has interviewed esteemed professors from the Institute of Biological Sciences at the University of the Philippines Los Banos. In a short but critical response, each professor picked and explained how some discoveries and events in the Genetic Timeline seems the most important for them.

GENEWS Team: “Which moment in the history of genetics seems most important?”

Ban on Genetic Discrimination in the Workplace, 1995

Protection under the American with Disabilities Act is extended to cover discrimination based on genetic information.¹

“I believe that the beautiful union between science and humanity is reflected in this landmark historical event. Here, we see that our moral and societal maturity developed further as we understood the unifying theme that connects us all.”

- Prof. Emmanuel T. Galang

Discovery of the Double Helix Structure of DNA, 1953

Francis H. Crick and James D. Watson described the double helix structure of DNA. They receive the Nobel Prize for their work in 1962.¹

“The elucidation of the structure of the genetic material is the most basic information that paved the way in the understanding of the genes and their actions and the development of various molecular tools.”

- Prof. Genaleen Q. Diaz, PhD

Genes are Made of DNA, 1952

Alfred Hershey & Martha Chase show that only the DNA of a virus needs to enter a bacterium to infect it, providing strong support for the idea that genes are made of DNA.¹

“It revolutionized genetics research by paving the way to recombinant DNA technology/genetic engineering and genetic manipulation studies such as gene-editing.”

- Prof. Aimee G. Cagalawan

DNA Transforms Cells, 1944

Oswald Avery, Colin MacLeod, and Maclyn McCarty show that DNA (not proteins) can transform the properties of cells --thus clarifying the chemical nature of genes.¹

“Avery, McLeod, and McCarty’s landmark experiment that showed the transforming ability of the DNA is one of the most important discoveries in the field of genetics and in science, in general. It encouraged scientists to shift focus and explore the possibility that the genetic material is made up of DNA and not protein, which is the popular candidate at that time. This new focus paved the way to breakthrough discoveries (including the structure of the DNA) which all led to our modern understanding of the role of DNA as hereditary material and the corresponding practical applications of this knowledge.”

- Prof. Aprill P. Manalang

First Screen of Metabolic Defects in Newborns, 1961

Robert Guthrie develops a method to test newborns for the metabolic defect, phenylketonuria (PKU).¹

“This discovery first established usefulness of studying genetics in relation to the detection, management, and prevention of certain diseases or disorders.”

- Prof. Joseph C. San Pascual

Rediscovery of Mendel’s Work, 1900

Botanists DeVries, Correns, and von Tschermak independently rediscover Mendel’s work while doing their own work on the laws of inheritance. The increased understanding of cells and chromosomes at this time allowed the placement of Mendel’s abstract ideas into a physical context.¹

“Though Charles Darwin have formulated the theory of Natural Selection, have observed variation in the population, and concluded that these variations are being passed on to the next generation, he cannot explain what causes these variations and how are they transmitted from generation to generation. Not until Mendel’s work was rediscovered and results of his experiment later becomes two of the most important laws of genetics: Law of Independent Segregation and Assortment.”

- Prof. Joan Christine O. Adajar

Heredity Transmitted in Units, 1865

Gregor Mendel’s experiments on peas demonstrate that heredity is transmitted in discrete units. The understanding that genes remain distinct entities even if the characteristics of parents appear to blend in their children explains how natural selection could work and provides support for Darwin’s proposal.¹

“Without this concept demonstrated by Mendel in his work on peas, maybe we will still wonder why and how variation is retained after so many generations. Heredity is passed on to subsequent generations as distinct units and combines with those from another parent to bring about variation. It is not some sort of a liquid thing that simply blends with that from the other parent, loses its identity afterwards, hence, cannot be passed on to many generations, and would decrease variation instead of increasing it. This concept supported Darwin’s proposal that nature selects the fittest from a great variety of individuals.”

- Prof. Diana Rose R. Gonzales

Discovery of Natural Selection, 1859

Charles Darwin wrote “On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life.”

“In 1973, evolutionary biologist Theodosius Dobzhansky wrote an essay entitled “Nothing in Biology Makes Sense Except in the Light of Evolution.” Personally, in a greater scheme of life, genetics has been providing, at the molecular level, essential information for understanding evolutionary mechanisms. This alone makes Darwin’s work truly remarkable. Having no available knowledge that time about genetics, he was able to expound evolution and natural selection exceptionally. Such viewpoints became hallmark concepts in biology that paved the way to look for ‘intrinsic factors’ in organisms responsible for inheritance and variation. Today, we call these ‘factors’ – genes, and this field – genetics.”

- Prof. Jickerson P. Lado

Development of DNA Fingerprinting, 1984

In 1984, Sir Alec Jeffreys discovered that humans have unique patterns of repeating DNA sequences called minisatellites. He later on developed the method of using DNA to establish identities of individuals which proved to be useful in forensic science.

“The discovery of human DNA fingerprints by Sir Alec Jeffreys is a perfect example of how curiosity coupled with the desire to impact society ignite many important scientific discoveries. He applied DNA cutting enzymes on samples of his lab mate and family. After discovering that bands are unique between individuals but shared by the child with his parents, its applications to human identification and parentage testing immediately dawned on him. That was when the revolutionary field of DNA forensics was born.”

- Prof. Jae Joseph Russell B. Rodriguez

These discoveries in Genetics are each vital for the attainment of its current fame and success as a science. These have allowed our scientists to see that our DNA, a mere small and simple sequence of bases in our cells, are the actual ones responsible for all complex traits and the molecular mechanisms that supervise them for those variations that differentiate each individual from another.

Some discoveries can be considered more essential or required but each discovery, big or small, has contributed fundamental evidence that built our current comprehension of the science. Each of these discoveries has contributed to our understanding of how Genetics and the machineries or tools associated with Genetics interact to make up all life forms. All these are equally crucial for the success of Genetics – one less could easily make our conception of Genetics fall apart.

¹Details of the events/discoveries in the history of genetics italicized above were quoted directly from the Genetic Timeline Factsheet of the National Human Genome Research Institute).

Reference:

National Human Genome Research Institute. (2014, April 14). Genetic Timeline. Retrieved from National Human Genome Research Institute: https://www.genome.gov/pages/education/genetictimeline.pdf