Margaret & Ruth Dayhoff

Dr. Margaret Dayhoff with young imaging specialist Dr. Ruth Dayhoff (About 1960)

Vincent Brannigan, “the family cook” and “very proud husband” sent this wonderful description of  three generations of STEM women, complete with pics.  The image above is of “Dr. Margaret Dayhoff with young imaging specialist Dr. Ruth Dayhoff (about 1960).”

Margaret Oakley Dayhoff  was valedictorian (class of 1942) at Bayside High School, Bayside, New York and from there received a scholarship to Washington Square College of New York University, graduating magna cum laude in mathematics in 1945. From there, Dayhoff undertook a Ph.D. in quantum chemistry, under George Kimball, in the Columbia University Department of Chemistry. In her graduate thesis, Dayhoff had pioneered the use of computer capabilities — i.e., mass-data processing — to theoretical chemistry; specifically, she applied punch card machines to calculate the resonance energies of several polycyclic organic molecules.

After completing her Ph.D, Dayhoff studied electrochemistry at the Rockefeller Institute from 1948 to 1951. In 1952, she moved to Maryland with her family and later received a research fellowship from the University of Maryland (1957–1959), working on a model of chemical bonding with Ellis Lippincott. She taught physiology and biophysics for 13 years, while becoming affiliated with the National Biomedical Research Foundation, a Fellow of the American Association for the Advancement of Science, a councillor of the International Society for the Study of the Origins of Life (1980) and acting on the editorial boards of DNA, Journal of Molecular Evolution and Computers in Biology and Medicine.

Frederick Sanger’s determination of the first complete amino acid sequence of a protein (insulin) in 1955, led a number of researchers to sequence various proteins from different species. In the early 1960s, a theory was developed that small differences between homologous protein sequences (sequences with a high likelihood of common ancestry) could indicate the process and rate of evolutionary change on the molecular level. The notion that such molecular analysis could help scientists decode evolutionary patterns in organisms was formalized in the published papers of Emile Zuckerkandl and Linus Pauling in 1962 and 1965. Dayhoff worked side by side with Lippincott and Carl Sagan on thermodynamic models of cosmo-chemical systems, including prebiological planetary atmospheres.

Dayhoff went on to pioneer the development of programmable computer methods for use in comparing protein sequences and deriving their evolutionary histories (in other words, discerning homologies) from their sequence alignments. Though this was before the days of massive outputs of sequence information by automated and other methods, Margaret Dayhoff anticipated the potential of computers to the current theories of Zuckerkandl & Pauling and the method which Sanger had engineered.

With Richard Eck, she published the first reconstruction of a phylogeny (evolutionary tree) by computers from molecular sequences, using a maximum parsimony method. She also formulated the first probability model of protein evolution, the PAM model, in 1966.

She initiated the collection of protein sequences in the Atlas of Protein Sequence and Structure, a book collecting all known protein sequences that she published in 1965. It was subsequently republished in several editions. This led to the Protein Information Resource database of protein sequences, which was developed by her group. It and the parallel effort by Walter Goad which led to the GenBank database of nucleic acid sequences are the twin origins of the modern databases of molecular sequences. The Atlas was organized by gene families, and she is regarded as a pioneer in their recognition. Her approach to proteins was always determinedly evolutionary. Margaret Oakley Dayhoff died of a heart attack at the age of 57.   David Lipman, director of the National Center for Biotechnology Information, has called Dayhoff the “mother and father of bioinformatics”.

In 1984 we created an award for a junior woman in biophysics named after Margaret.

Dr Margaret Dayhoff’s husband was the late Dr Edward Dayhoff, who was endlessly supportive of Margaret’s ambitions.  They had two daughters,  Ruth and Judith.

Judith Dayhoff Ph.D. has a Mathematical Biophysics  PhD from U of Pennsylvania and is the author of Neural network architectures: An introduction and coauthor of Neural Networks and Pattern Recognition. She is also the author of many journal articles.   She has 3 children.

Ruth Dayhoff M.D.  graduated Summa cum laud in Mathematics from the University of Maryland and focused on Medical Informatics while doing her MD at Georgetown University School of Medicine.

--) Typical Math Girl --)  Ruth at 21

Vincent captioned the photo above as
🙂 Typical math girl 🙂        Ruth at 21.

Ruth was a founding Fellow of the American College of Medical Informatics.  She is recognized throughout the world as a pioneer in the integration of Medical Imaging.  She was chosen for the National Library of Medicine’s project on the 200 women Physicians who “changed the face of medicine.”

She is director of Digital Imaging in Medicine for the United States Department of Veteran’s Affairs.


The picture above is of Ruth and Vincent with their daughters, Margaret and Eleanor.   Margaret Dayhoff-Brannigan is completing a Ph.D at Johns Hopkins in Virology.  Margaret just presented Ruth with her first grandchild.  So Ruth and her Mother would have qualified as STEM Grandmas. Eleanor is an attorney and specialist in protective orders for women.

Dr. Ruth Dayhoff with daughter Margaret and Grandson Joshua

Dr. Ruth Dayhoff with daughter Margaret and grandson Joshua.

Vincent noted that in addition to cooking and child rearing he did manage a career for himself. He is Professor Emeritus of Law and Technology at the University of Maryland School of Engineering.

I love Vince’s first email to me so much, I am including it below.

So you are looking for Grannies with STEM

My Late Mother in law Was Dr. Margaret O Dayhoff  (Mother of Bio Informatics)

My wife and now a Grand mother is Dr Ruth Dayhoff  Inventor of the Vista imaging system

My Daughter is the Hopefully soon to be Dr. Margaret Dayhoff- Brannigan  (who knows what she does at Johns Hopkins with recombinant Yeast DNA)

My Mother was a Naval officer in WWII.

Me, I am the family cook

How can I help?

Related links:

Wikipedia page

Discussion of work



This entry was posted in Chemistry, Mathematics. Bookmark the permalink.

3 Responses to Margaret & Ruth Dayhoff

  1. Hi folks–I’m looking for the Dayhoff family for a couple of reasons. The details are here: If anyone has contact info and could shoot them an email, I’d appreciate that. I can be reached on twitter @mem_somerville or via Google+ from the link on my twitter page.

  2. I am Margarets son in law Prof. Vincent Brannigan I am not on twitter and you seem to have a total wall of silence

  3. Pingback: Margaret Oakley Dayhoff | Introductions Necessary

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