Jean Elizabeth Garrigan, who later changed the spelling of her first name to Jeanne, was born in Brooklyn on March 6, 1943. Her father, James Philip Garrigan, was a businessman and her mother, Mary Eileen (Harley) Garrigan, a homemaker.
They moved to Rutherford, N.J., where Jean was educated by Dominican nuns. Her husband said the nuns had given her a strong foundation in morality and instilled in her “a feeling that the world should be civil.”
She received her bachelor’s degree in social psychology from Harvard in 1968 and her doctorate in sociology and anthropology from Brandeis University in 1973.
Her first marriage, in 1963 to the painter Robert Guillemin, ended in divorce. (He died in 2015.) They had two sons, John and Robert, whom she raised for a time as a single mother. She married Dr. Meselson in 1986.
The couple spent their summers in Woods Hole, Mass., on Cape Cod, where they hosted a regular salon that brought together humanists and scientists. In Cambridge, Dr. Guillemin was a member of a writing group with four other women who met every month for 30 years to discuss their works in progress.
In addition to her husband and her sons, she is survived by a stepdaughter, Zoe Meselson Forbes; two sisters, Patricia and Eileen Garrigan; a brother, Russell Garrigan; and five grandchildren. Another brother, Brian Garrigan, died in 2018, as did another stepdaughter, Amy Meselson.
Dr. Guillemin was a professor of international relations and anthropology at Boston College, where she taught for 33 years. She was also a senior fellow in the security studies program at M.I.T. from 1999 until her death.