Microbial Sciences

Microbial sciences is an interdisciplinary approach to studying the impact of microbes at scales from global ecosystems down to single-celled microenvironments. The academic program emphasizes the joint study of species diversity, metabolic function, geochemical impact, and medical and pharmaceutical applications of microbial sciences. Faculty affiliated with the Microbial Sciences Initiative (MSI) include members from Molecular and Cellular Biology, Organismic and Evolutionary Biology, Earth and Planetary Sciences, Chemistry and Chemical Biology, the School of Engineering and Applied Sciences, Harvard Medical School, Harvard School of Public Health, and the Forsyth Institute.

The MSI secondary field is intended to provide a strong foundation in interdisciplinary microbial sciences to students who have sufficient preparation in other natural sciences, mathematics, or engineering. In particular, the MSI curriculum is intended to (i) be interdisciplinary, (ii) not be specifically biomedical, and (iii) incorporate elements from physical sciences as well as life sciences . An important aspect of the MSI secondary field is the laboratory component, which provides hands-on experiential learning to all students.

REQUIREMENTS: 5 courses (20 credits)

  1. Two MSI cornerstone courses. All secondary field students will take Microbiology 210: A Microbial Planet and Life Sciences 100r (the microbial sciences laboratory project component). Other research project courses, such as those numbered 91r or 99r, may be allowed to substitute for Life Sciences 100r, if they have the appropriate microbial emphasis. No substitutions will be accepted for Microbiology 210.
  2. One introductory course. All secondary field students will take one approved introductory course below the 100-level. The eligible courses will be selected from departmental offerings in FAS that contain material relevant to providing a foundation in microbial sciences. Examples include Earth and Planetary Sciences 56: Geobiology and the History of Life, Chemistry 27: Organic Chemistry of Life, and MCB 60: Cellular Biology and Molecular Medicine.
  3. Two additional microbial courses at the 100-level or above. A list of such courses is available on the MSI website. Examples include Life Sciences 120: Global Health Threats, Earth and Planetary Sciences 186 or 187: Low Temperature Geochemistry I or II, and Microbiology 201: Molecular Biology of the Bacterial Cell.
  4. MSI tutorial: non-credit. Students are encouraged, but not required, to attend the MSI chalk-talk series, which is offered every Friday from 8:45-9:30 am. The location is announced weekly at http://www.msi.harvard.edu/events/fridays.html.


All courses must be taken for a letter grade in order to count toward secondary field credit, and normally C is the minimum acceptable grade. The only exception is approved Freshman Seminars, which are graded SAT/UNS.

Of the one introductory course and two additional microbial courses, two must be significantly outside the student's primary area of concentration, providing each student substantial interdisciplinary experience.

Some courses for Microbial Sciences credit may have hidden prerequisites. Students should plan appropriately, as a prerequisite cannot be counted for Microbial Sciences credit unless it satisfies requirement 2 above.

Students may receive credit for Life Sciences 100r twice. Students electing to do this may count one semester towards the Microbial Sciences secondary field and one towards their concentration, or they may count the second semester as one of their two 100-level electives in the secondary field. A single semester of Life Sciences 100r may not be double-counted.

Courses from study abroad or Harvard Summer School could count toward secondary field credit if approved by the MSI Steering Committee prior to the student's enrollment in these courses. The student must petition the MSI Steering Committee in the semester prior to their intended enrollment in such courses and must provide a syllabus or detailed course summary to the committee. A petition to retroactively consider substituting one relevant Freshman Seminar for one of the two 100-level elective courses also will be considered.


Students will submit an application to MSI for the secondary field no later than the Study Card due date of their penultimate term. This application form is available on the MSI website. Additionally, students must file online with the Registrar's Office through the Secondary Fields Web Tool.

Students are encouraged to be active participants in the MSI community. Secondary field students will be invited to all MSI events and activities. Undergraduate participation will provide opportunities to get acquainted with graduate students, post-docs, and members of the faculty.

Students interested in pursuing a secondary field in Microbial Sciences should contact MSI Head Tutor Ann Pearson (pearson@eps.harvard.edu, 384-8392, Hoffman Lab G13) or MSI Executive Director Karen Lachmayr (klachmay@fas.harvard.edu).