The Heroines of Genetics

Written by: Jamie Fernandez, Content Specialist, B.Sc. in Genetics

Picture a woman, a strong and confident woman in a white coat standing in a laboratory performing an experiment. Her intelligence has earned her the right to be there, but it is her ambition and determination that has gotten her there. She is a minority in her field and is likely not being given equal opportunities as a man in the same position as her. 

Only about 30% of researchers are female and they often receive lesser research grants in comparison to those of their male colleagues [1]. Even in this modern day, the fact that women only account for about a third of research scientists indicates that a gender equality gap is prevalent but in the 1940s and 1950s, women in research were even more rare. 

In 1944, Oswald Avery (1877-1955) identified DNA as the “transforming principle”. In other words, he confirmed that DNA is in fact the blueprint of life [2]. This discovery inspired a great drive to research and understand  DNA. There are many who can be accredited to contributing to the basic understanding of DNA and among them are two incredible women who published significant research in genetics; however, their names are often left out of the history books.

Figure 1: The structure of DNA

If you have a look at Figure 1, you will see the fundamentals of DNA. Today, this is a basics lesson for a high school biology class thanks to the work done by Marie Maynard Daly (1921-2003).

Photo: Marie Maynard Daly

Daly was born in Queens, New York in 1921 and in 1942 she graduated magna cum laude from Queens College with a bachelor’s degree in chemistry. She then went on to join the doctoral program at Columbia University and in 1947, she became the first African-American woman to receive a PhD in chemistry. Her research focused on the digestive enzyme, amylase. Daly’s postdoctoral research led her to Alfred E. Mirsky at the Rockefeller Institute in New York. It was here that she spent 7 years researching the building blocks of DNA. Through  a series of sophisticated experiments, Daly identified that the nucleobases adenine, cytosine, thymine and guanine are main nucleobases in DNA as they are present in the most significant amount [3]. 

This wasn’t her only contribution to the field of genetics, as she also discovered that there are different types of histones. A histone is a very special protein that DNA wraps around when it forms the chromosome structure. Understanding that there are different types of histones led researchers in later years to discover that these different histones contribute to how DNA is “read” to express certain genes at different times or in different cells. This is one of the basic principles in epigenetics, changes to your genetics that don’t involve changing the DNA sequence[4], [5]. 

Daly also did significant research in the understanding of the causes of atherosclerosis (the build of fat and cholesterol in the arteries) [6]. She became a professor at the Albert Einstein College of Medicine in 1960 and retired in 1986. Daly was more than a researcher, she was also an activist and fought to get more students of colour enrolled in graduate science programs and medical schools. In 1988, she started a scholarship for minority students to study science at Queens College. This scholarship was in honour of her father, who had to drop out of his studies of chemistry at Cornell University for financial reasons [5]. 

Daly’s research gave important insight into what DNA is made of, but what about the structure of DNA? The names that most likely came to your mind are James Watson and Francis Crick because they won the Nobel Prize in Physiology or Medicine in 1962 for their discovery of the molecular structure of DNA. However, in recent years, much light has been shed on the truth of this discovery and the contributions of Rosalind Elsie Franklin (1920-1958). 

Photo: Rosalind Elsie Fraklin

Franklin graduated from University of Cambridge in 1941 with a degree in physical chemistry. From there she did significant research on the chemistry of carbon and coal for her doctoral thesis. In 1951, Franklin began working at the biophysical laboratory at King’s College, London where she used X-ray diffraction methods to study the structure of DNA [7]. After years of hard work to develop a method for successfully obtaining X-ray diffraction images of DNA, she took the first image of DNA, the now famous Photo 51 (Figure 2). In 1953, Watson visited King’s College London and was shown Photo 51 by one of Franklin’s colleagues, Maurice Wilkins (who won the Nobel Prize in 1962 alongside Watson and Crick), without Franklin’s knowledge. This built the foundation of Watson and Crick’s research and led them to the same conclusion that Franklin reached in her own calculations based on Photo 51. Watson and Crick’s research and Franklin’s research were both published in the same journal but since Franklin’s research was placed after Watson and Crick’s, the impression was that her research only confirmed theirs[8]. 

Figure 2: Photo 51

Franklin was overlooked by her male colleagues and was a victim of gender-based harassment in her work environment [9]. Franklin went on to research the tobacco mosaic virus before she sadly passed away from cancer in 1958 at the age 37 [7].

Franklin did not receive recognition for her contributions to genetics but her legacy has helped to forge the path for women to gain recognition for their work. Notably we saw this in 2020 when Jennifer Doudna and Emmanuelle Charpentier were celebrated for their work on the CRISPR-CAS9 system and won the Nobel Prize in chemistry for the development of this method of genome editing [10]. 

These unsung heroines, Marie Daly and Rosalind Franklin, are proof that passion, determination and work-ethic can overcome society’s preconceived notions of gender, race, ethnicity and economic status. Their stories stand as pillars of inspiration in the fight for equality, especially for those young girls who dream of making their mark in this world while wearing a white lab coat. 

References:

[1]   “International Day of Women and Girls in Science | United Nations.” [Online]. Available: https://www.un.org/en/observances/women-and-girls-in-science-day. [Accessed: 09-Aug-2022].

[2]   “1944: DNA is \"Transforming Principle\".” [Online]. Available: https://www.genome.gov/25520250/online-education-kit-1944-dna-is-transforming-principle. [Accessed: 11-Aug-2022].

[3]   M. M. Daly, V. G. Allfrey, and A. A. E. Mirsky, “Purine and Pyrimidine Contents of Some Desoxypentose Nucleic Acids.”

[4]   “Marie M. Daly - Life, Facts & Family - Biography.” [Online]. Available: https://www.biography.com/scientist/marie-m-daly. [Accessed: 11-Aug-2022].

[5]   “Marie Maynard Daly | Science History Institute.” [Online]. Available: https://www.sciencehistory.org/historical-profile/marie-maynard-daly. [Accessed: 11-Aug-2022].

[6]   Q. B. Deming et al., “The Effect of Variations in Blood Pressure on the Cholesterol Content of Serum and Tissues and on the Development of Atherosclerosis in Rats on a High Cholesterol Diet.”

[7]   “Rosalind Franklin | Biography, Facts, & DNA | Britannica.” [Online]. Available: https://www.britannica.com/biography/Rosalind-Franklin. [Accessed: 11-Aug-2022].

[8]   “Photograph 51, by Rosalind Franklin (1952) | The Embryo Project Encyclopedia.” [Online]. Available: https://embryo.asu.edu/pages/photograph-51-rosalind-franklin-1952. [Accessed: 11-Aug-2022].

[9]   B. L. Benderly, “Rosalind Franklin and the damage of gender harassment,” Science (80-. )., Aug. 2018.

[10] L. Westermann, B. Neubauer, and M. Köttgen, “Nobel Prize 2020 in Chemistry honors CRISPR: a tool for rewriting the code of life,” Pflugers Arch., vol. 473, no. 1, p. 1, Jan. 2021.