Sister Miriam Michael Stimson turned early models of DNA inside out

Not everyone thinks of a Catholic nun when they think “scientist.”

Laura Mast

Environmental Engineering

Georgia Institute of Technology

Children as young as seven years old draw scientists as predominantly men (the lab coat and crazy hair are bonus). While this trend is changing, I’ll hazard a guess that not everyone might think of a Catholic nun when they think “scientist.”

For Sister Miriam Michael Stimson, though, these identities were always fully intertwined. She was always interested in human health and medicine, having grown up around illness: her older brother had polio, her sister had a heart condition resulting from an infection, and her mom had such high blood pressure after she gave birth to twins that she suffered from memory loss.

Illustration of Maria Stimson, nun and DNA pioneer.

Matteo Farinella

Stimson studied chemistry at Siena Heights College, a small Catholic school in Michigan, going on to earn her PhD at the Institutum Divi Thomae in Cincinatti. She returned to Siena Heights to teach and to open a research lab, where she studied cancer and wound-healing treatments (including one that led to the creation of Preparation H).

Her most important work, however, focused on infrared spectroscopy, a technique that maps out a chemical's structure. The atoms in a molecule are always in motion, with the chemical bonds between them constantly bending and stretching. These bends and stretches are unique to the atoms involved – a carbon to oxygen bond is different from a carbon to hydrogen bond,  and a big stretch behaves differently than a little bend. These small differences allow us to map out what a complex molecule looks like.

To see this chemical “fingerprint”, however, you have to know what to look for. For Stimson, existing methods didn’t cut it: there was often too much interference in the resulting spectra to clearly see the stretches and bends she was seeking. 

Stimson solved this problem by mixing the chemical she was studying with potassium bromide and pressing it into a nearly transparent pellet. Potassium bromide, made up of a positively charged potassium ion and a negatively charged bromine ion, doesn't have stretches and bends, so it doesn't interfere with the spectrum. Of her new method, she said “there was an absence of interfering bands, lower scattering losses, higher resolution of spectra, better control of concentration and homogeneity of sample, ease in examining small samples, and possibility of storing of specimens for further studies.” 

Using potassium bromide opened up a new world for Stimson and other chemists to study both simple and complex structures, and led Stimson to her most consequential contribution: the discovery of the structure of DNA.

Unlocking DNA was arguably the most critical scientific issue of the time, mesmerizing the most famous minds in science like James Watson, Francis Crick, and Linus Pauling. Watson, Crick, and Pauling, however, all proposed models with a fundamental flaw: they were inside out. They had the bases on the outside, not the inside where they belong.

Armed with her potassium bromide technique, Stimson was able to not only confirm the structure of DNA nucleotide bases, but also study how they were connected in the DNA double helix structure, literally turning the flawed models inside out.

Stimson has not received much credit for her contribution to DNA; the Nobel Prize for the discovery of DNA went to Watson, Crick, and Maurice Wilkins (a colleague of Rosalind Franklin) in 1962. She was, however, invited to lecture at the Sorbonne in Paris, the second woman ever following Marie Curie, and she received international recognition for her extensive work in spectroscopy.

She was also able to make an impact at her small home school in Michigan, where she was known as M2 (that’s M squared to you). In addition to running her cancer chemistry lab for more than 30 years, she founded an addiction counseling program and introduced undergraduate level research to the university.

While most sources don’t describe how Sister Miriam Michael Stimson thought about her work in the context of her religion, one article describes her saying, “Sister Miriam saw her scientific work as a means of discovering truth that would lead us closer to God.” Her former student and colleague, Sister Sharon Weber, said after Stimson's death, "the spirit of the Dominican search for truth was a very high value of hers, that in coming to know truth we know more about God." 

While now scientists overall tend to be considerably less religious than the general population (33% vs. 83%, respectively, according to a Pew study in 2009), historically this has not been the case. Many of the greats – Galileo, Newton, Descartes, Pascal – were deeply religious, and many Nobel prize winners have also been publicly religious like Dr. Christian Anfinsen (biochemistry of RNA), Dr. Arthur Schawlow (on lasers), and even Dr. Arno Penzias of Bell Labs (for the first observation of the universal microwave background radiation). 

A recent study from Rice University found that 45% of scientists in the UK don’t believe in God, compared to 18% of the public. Sociology professor and lead author Elaine Howard Ecklund attributes this to not simply intellectualism, but also to social forces, saying:

“Elite scientists might express less religiosity because they assume that, as elite scientists, they are supposed to be or need to be less religious to fit a professional ideal. Because they might already be on the fringes of that professional ideal in the first place, non-elite scientists may feel less social and cultural pressure to further conform to it.”

This isn’t the first time this conversation has come up, nor is it the last. Most recently, President Barack Obama nominated Frances Collins, famous geneticist and outspoken evangelical Christian to be director of the  National Institutes of Health. As we continue the conversation around who can be a scientist, what scientists are supposed to act like, and how communities in science can be more inclusive, Sister Miriam Michael Stimson may serve as an example of someone who deeply cared about humanity and used her skills in the lab to advance knowledge for all humankind.