top of page
  • Writer's pictureDale DeBakcsy

Broken Hearts and Nuclear Secrets: Marie Maynard Daly, America's First Black Woman Chemist.

The years of the Second World War gifted to American feminism one of its most enduring icons in the form of Rosie the Riveter.  She was the symbol of a wave of women joining the industrial workforce to support the grand fight against European fascism, and so potent is that symbol still that when we think of women in the 1940s, it's hard to imagine our way past the welding torch wielding women of the aeronautical and steel industries.  But as important a breakthrough as those industrial jobs were, there was another, less publicized revolution contemporaneously at work: women's sudden entry into America's laboratories.


Appointments that would have been handed as a matter of course to male scientists a decade earlier were, in the surge of wartime research, often enthusiastically thrown into the hands of qualified women by a nation seized with the possibilities of science to win a war and remake a society.  There are many stories to tell in this vein, but few as satisfying as that of Marie Maynard Daly (1921-2003), the first black woman in America to earn a PhD in chemistry, and an important early researcher not only of nucleic acids, but of the effects of cholesterol and diet on hypertension.

Daly's father came to New York from the West Indies to study chemistry at Cornell University when a lack of money forced him to abandon his education mid-stream and take up a career in the postal service.  He was determined that his children would have the opportunities denied him, and pushed them to read as much as possible.  Young Daly took advantage of her grandfather's library, filled with biographies of scientists.  In particular, she was attracted by Paul De Kruif's Microbe Hunters (1926), a book that invariably comes up in mid-century microbiologists' accounts of their early inspirations.  

Encouraged at home, and possessed of a unique self-motivation to independently study the history of science, Daly excelled at Hunter College High School, and her teachers, recognizing her talents, gave her college-level chemistry material to study while still in high school.  As a resident of New York City Daly had the opportunity to study for free at the newly established Queens College, where she graduated magna cum laude in 1942.  That college offered her work right away as a part-time lab assistant, while a separate fellowship allowed her to study for her Master's at New York University, which she obtained in 1943.  

So far, Daly's progress was little short of a triumphal procession, but now the specter that haunted her father's academic career cast its shadow over hers in turn: money.  PhD programs were costly, and Daly was prepared to work at the lab as long as it took to save up the necessary funding, but that's when World War II's thirst for new scientists, and the funding that came in its wake, intervened.  She received a fellowship to work at Dr. Mary Caldwell's lab at Columbia University.  Caldwell (1890-1972) had received her PhD at Columbia in 1921 and went on to become its first woman chemistry professor, carrying out research over the next forty years that made her a world authority on the digestive enzyme amylase.  

Formal but encouraging, Caldwell took Daly firmly under her wing, as she had other promising women chemistry students, helping her choose her thesis topic on the chemicals produced when pancreatic amylase digests corn starch.  Five years later, in 1948, Daly received her PhD and, after a brief hiatus in the lab of Dr. Herman Branson to once again sort out funding, she began work under an American Cancer Society grant at the Rockefeller Institute.  

Let's take a step back at this moment to appreciate how far Daly had come.  Six short years after graduating from college, Daly had become the nation's first Black female doctor of chemistry, obtained a grant from the American Cancer Society, and found a position at one of the nation's premiere research institutions alongside Nobel laureates, all on the strength of her own mind and passion for science.  At Rockefeller she studied cell nuclei and their contents.  These were the years before Watson and Crick and Franklin had discovered the structure of DNA (1953), and before Hershey and Chase confirmed its role as the carrier of hereditary information (1952), when the nucleus and its contents were still the domain of a dedicated minority of researchers.  

It was Daly's job to study nucleic acids, and in the process she made discoveries about the properties and content of histones (the proteins around which DNA wraps itself, and which play important roles in gene expression), and about purines and pyrimidines.  These nucleic acid components determine the A, G, C, T, and U coding of DNA and RNA, and Chargaff's contemporaneous discovery of their frequency relations was a major clue in Watson, Crick, and Franklin's decoding the structure of DNA.  So important was her work on nucleic products that it was cited by Watson and Crick in their Nobel address.

In 1955 Daly returned to Columbia University, to the College of Physicians and Surgeons and an entirely new realm of study: the chemical and nutritional factors contributing to hypertension.  Her studies were the first to point to the role that cholesterol plays in clogging arteries and therefore heart disease, and also established the roles that smoking, sugar, and endocrine factors play in the worsening of hypertension.  Having worked out contributing factors to hypertension, she then went on to study how both aging and hypertension impacted the function of the circulatory system generally.  

After 1971, Daly switched research topics once again, this time to the study of creatine in muscle tissues.  Muscles are massive burners of ATP, the body's universal energy carrier.  When ATP is harvested for energy, a phosphate group is removed, and it becomes ADP.  Creatine is involved in the process of recycling those ADP molecules, attaching a new phosphate, and thereby creating new ATP to be used in muscle and brain tissues.  In 1980 she reported in "Uptake of Creatine by Cultured Cells" the temperature and ion conditions under which creatine was best absorbed by muscle tissues.

After four decades of research that encompassed pioneering nuclear studies, a thorough study of the causes and consequences of hypertension, and fundamental work in muscle energy recycling systems, Daly retired in 1986 to her flute playing, her garden, her beloved dogs, and to the creation of a scholarship for black students interested in the physical sciences.  She died on October 23, 2003.


The most thorough account of Marie Daly's life and science is given in African American Women Chemists (2012) by Jeannette E. Brown, but she also has a shorter feature in Wini Warren's Black Women Scientists in the United States (1999) and in James Kessler's Distinguished African American Scientists of the Twentieth Century (1996), which costs $98 as a new hardback but which you can grab used for under $10 - what a deal!


bottom of page