by Wei Li

Everyone knows that having high cholesterol in your blood is not a good sign — it can lead to high blood pressure and clogged arteries (also known as atherosclerosis), resulting in heart diseases or stroke. However, what we now consider common knowledge, required years of research to discover. An important contributor to what we know about cholesterol and high blood pressure is Marie M. Daly, the first Black American woman in the United States to earn a Ph.D. in Chemistry.

Marie Daly was born in Queens, New York City, in 1921. She grew up reading a lot about scientists and their achievements, fostering a love of science from a young age. Her father had wanted to become a chemist, but had to quit college because of a lack of funds. This motivated Daly to continue her father’s dream of becoming a scientist and major in chemistry in Queens College. After graduating college and obtaining a Master’s degree in New York University, she enrolled in a Ph.D. program at Columbia University, where she obtained a Ph.D. in Chemistry in just three years.

After her graduate education, Daly worked on a lot of different important research areas, and one of them was understanding the causes of atherosclerosis. In her study published in the Journal of Experimental Medicine, she conducted multiple rats studies where she looked at their cholesterol levels, their blood pressure, as well as how damaged or clogged their arteries were. She found a strong correlation between high blood pressure and having high cholesterol levels in the blood, which was a groundbreaking discovery at that time. This discovery served as a foundation for future research into the causes of atherosclerosis and other high blood pressure-related diseases.

In addition to her work in cholesterol and atherosclerosis, Daly also worked on characterizing histones, a type of protein that bundles our DNA into tiny packs of coils, forming the chromosomes in our cells. Histones are very important for gene expression — depending on how tightly they pack your DNA, they determine whether certain parts of your DNA are able to be turned on or “expressed”. However, back in the 1950s, nobody really knew what histones were or what they were made of. In a study published in the Journal of General Physiology, Daly painstakingly isolated histones from various animals to determine their properties and composition. Her work contributed to our basic understanding of histones and, ultimately, the organization of our DNA.

Marie definitely accomplished a lot as a scientist, but beyond her scientific achievements, she had also made improvements in her community. In honor of her father, who could not finish college, she started a scholarship fund at her alma mater, Queens College, to assist minority students majoring in physical sciences. Her legacy in both scientific and financial contributions will definitely live on forever.

---

Wei Li is a third-year Ph.D. student in the Chemistry and Chemical Biology program at Harvard University.

Cover image by Gordon Johnson from Pixabay

This biography is part of our “Picture a Scientist” initiative. To learn more about the amazing men and women who paved the way for modern scientific discovery, check out our homepage.