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Molecular and Cellular Biology

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Questions about these requirements? See the contact info at the bottom of the page. 

PhD Degree Requirements

Graduate students belonging to the Molecules, Cells, and Organisms (MCO) training program are supported by an interdepartmental and interdisciplinary collective of faculty composed of members of the MCB as its nucleus but with support from members of Chemistry and Chemical Biology (CCB), Organismic and Evolutionary Biology (OEB), Stem Cell and Regenerative Biology (SCRB), Department of Physics, and the School of Engineering and Applied Sciences (SEAS).  

Required Coursework

The MCO curriculum offers unique courses designed to prepare students for success during their PhD and beyond. Coursework takes place in the first year of study and includes two terms of MCB 297 (Method & Logic), MCB 208 (Talking About Science), and MCB 296 (Scientific Journeys) as well as a quantitative biology course, chosen based on Harvard's math placement exam, and in consultation with program leadership. Students will also take MCB 327 (Life Sciences Pedagogy), a course taught by a Bok Center Pedagogy Fellow, which will prepare students to be effective teaching fellows in their G2 year. 

Students are also required to take at least one elective course, which they will choose in consultation with MCO program leadership.  

In addition to academic coursework, all graduate students in the program must complete an eight-hour workshop in the Responsible Conduct of Research (RCR) to be completed by the end of the first year of study. Additionally, students are required to take an RCR refresher course after the fourth year of study.

In accordance with the Harvard Kenneth C. Griffin Graduate School of Arts and Sciences (Harvard Griffin GSAS), all degree candidates must maintain a grade point average equivalent to 3.0 or better to continue in the program. Satisfactory progress is reviewed annually and students who fall below the grade minimum will ordinarily be given one term to improve their grades.

Laboratory Rotations

With nearly 60 participating faculty labs, the MCO program provides an invaluable opportunity for graduate students to observe and participate in a variety of laboratory environments. MCO G1 students carry out three different lab rotation projects during the first year. Following the three intense five- to seven-week rotation periods, students will select a suitable home lab by the end of May of the spring term. 

The rotations will expose students to a wide range of research concepts, techniques, and model systems. Additionally, they offer networking opportunities and serve to introduce G1 MCO graduate students into our extended scientific community. The ultimate goal of making the rotation period intense and immersive is to help students succeed in finding a PhD lab that is right for them and in which they will thrive scientifically in the years ahead. 


Nanocourses are offered in a broad range of topics during the course of an academic year. Participation in relevant nanocourses is encouraged for all students in the MCO training program.

Dissertation Research

Each student arranges for a permanent faculty dissertation advisor by the middle of the second term of their first year and begins dissertation research thereafter.

Nonterminal Master of Arts (AM)

Students may apply for a nonterminal master's degree following successful completion of all G2 requirements including the candidacy examination, G2 DAC meeting, coursework, and teaching one required course.


Each student is required to serve as a teaching fellow for one term during their G2 year. Students are expected to teach either one of the large introductory undergraduate laboratory-based courses such as Life Sciences 1a or 1b, Life and Physical Sciences A, MCB 80, or MCB 60, or a small, discussion-based advanced course. Teaching beyond the requirement is encouraged but requires prior approval from the student’s advisor(s), dissertation committee members, and the MCO program leadership.

Candidacy Examinations and Evaluation

To advance to PhD candidacy, students are required to successfully complete the candidacy exam by June 30 of their G2 year. The candidacy examination committee is composed of three faculty members from the MCO training program, which students will select in consultation with their dissertation advisor. The purpose of the candidacy examination is to assess the student’s progress in their home lab during their G2 year and, based on these past accomplishments as well as future potential, determine whether the student should be advanced to PhD candidacy. In addition, this examination places emphasis on the following scholarly abilities: a superior knowledge of the specific topic they are working on and a broad familiarity of how it connects to neighboring areas of biology; firm grasp of the paradigms and open challenges in their chosen field of study; and, most critically, the ability to design and correctly interpret decisive experiments aimed at falsifying competing hypotheses. 

With advice and assistance from their advisor, the student prepares a dissertation research proposal that outlines the plan for PhD research. The advisor must approve the proposal and the student will distribute this document to all committee members and the graduate office at least one week prior to the exam.

The advisor is not a member of the candidacy examination committee and does not attend the exam itself. However, the advisor should inform the committee about the student’s proposal and work. This occurs in a pre-exam session without the student present.

The examination committee considers all the information available to inform the candidacy examination decision. This may include the student’s academic record in courses; the student’s rotation reports and the accompanying evaluation from rotation supervisors; the advisor’s report on research progress; and the written research proposal.

The examination is structured around the student’s presentation of the proposed research project. Though the project itself is not a target of the exam, it provides a good starting point for assessing the student’s preparation. To enhance the “real-time” character of the discussion, students are not allowed the use of visual aids aside from drawing their own figures on a chalk or whiteboard. Examiners are free to interrupt the presentation at any time to explore various threads in more detail. Each examiner is expected to lead at least one line of inquiry outside of the specific topic of the research proposal into areas deemed essential basic knowledge in modern biology.

The exam has three possible outcomes:

  1. Pass: The student continues in the program toward the PhD. 
  2. Pass with condition: The student must complete the conditions set by the committee (for example, teaching or taking a specific course, or rewriting the research proposal for approval by the committee).   
  3. Fail: This indicates major deficiencies in the candidate’s preparation. The student has the opportunity to retake the candidacy exam only once in this situation. The second exam has outcomes of pass or fail only.

Dissertation Advisory Committees (DAC)

MCO PhD candidates report their progress to a dissertation advisory committee (DAC) at the beginning of each academic year to encourage forward thinking. The DAC may require more frequent meetings depending on the student’s progress, especially in the completion phase. The student invites three to four faculty members to join the DAC. The committee members may be the same as the candidacy exam committee, or the student may elect to choose new members. Membership must include at least two faculty members from the MCO training program. 

DAC meetings serve as an opportunity for the student and advisor to assess progress and plans and receive feedback for the year (next DAC) and longer term (Defense). Integral to these meetings is the preparation of a DAC report that summarizes progress, challenges, and future directions. The substance and format of the report will evolve as students progress through the program. The advisor should be involved in the planning, drafting, and finalizing stages of the DAC report. 

The DAC has four main missions:

  1. To serve as an advisory committee that will provide professional advice on all aspects of the dissertation project—from experimental paradigms to project feasibility and timing to the scientific impact of the work.
  2. To help monitor the student’s progress and ensure that major objectives and standards for completion of the dissertation are being met. In this capacity, the DAC determines whether the student’s research meets the requirements of the program and when the student may begin writing the dissertation.
  3. To help resolve any conflict between student and advisor or other lab members.
  4. To serve as liaison to the department and training program leaders as well as graduate administration.

Students submit a report to each committee member and to the Graduate Office one week in advance of their DAC meeting. The report’s cover page should be signed by the student and advisor and include the date, time, and location of the meeting. The format of the student DAC report mimics a draft research manuscript in which students are required to sketch the main figures of a paper(s) and add placeholders for data that they plan to collect. Guidelines are provided.

PowerPoint slides are permitted at DAC meetings. The main part of a student’s DAC meeting entails a 20- to 40-minute student presentation consisting of results (if any) along with plans. Like the candidacy exam, committee members will typically interrupt the presentation with questions, and the presentation is followed by a discussion of progress and future plans and aims. Students should be concise in the report and consistent with format. Unlike the candidacy examination, advisors are encouraged to attend. The student’s advisor is not a member of the DAC and should endeavor to let the student present their own progress. It is critical that the advisor briefs the DAC on the student’s activities, preferably in a private session with the DAC prior to the student’s report, but this can be done via an email to the DAC members prior to the meeting. Whether the advisor stays or not, in order to provide an opportunity for both the student and advisor to communicate with DAC members on a confidential basis, the meeting will start with first the student leaving the room, and then the advisor leaving the room. When the student is not present, the advisor will have a chance to present their assessment of progress and whether the student is on course to graduate in a timely fashion. When the advisor is not present, the student may likewise communicate their assessment of progress and whether the advisor and the laboratory environment are providing the support needed. This is also an opportunity, if necessary, to share with the committee any other problems of a confidential nature with which the student may need help.

Dissertation Defense

To schedule a defense, students are required to have published or submitted at least one first-author manuscript. Three to four years of full-time research are usually required for completion of the PhD degree. Students are expected to complete the program in their fifth year of study, and support is usually only provided until the end of the fifth year. Advisors must agree to support students beyond their fifth year of study.

Completed research is presented for approval as a written dissertation. Candidates should submit a copy of their dissertation to each member of their dissertation committee as well as the Graduate Office at least two weeks prior to their defense. The dissertation committee is often identical to the DAC but may be changed with the approval of the Graduate Program Office.

Granting of the degree requires the approval of the candidate’s dissertation committee members who review the dissertation and examine the student on the contents of the dissertation. Candidates will also be called upon to demonstrate the ability to formulate and defend original ideas on scientific topics not directly related to the subject of the dissertation.


The dissertation should include an abstract of not more than 350 words, stating the purpose, main results, and research conclusions. In addition, ordinarily, a dissertation must contain an introductory and concluding chapter, each no less than five double-spaced pages. The introductory chapter should set out the overall theme of the dissertation, describe the state of knowledge in the field before the student’s work began and any important advances made by others during the student's dissertation research, and describe the progression of the following chapters. The concluding chapter should attempt to draw overall conclusions from the dissertation research work, describe directions in which it could be usefully extended, and describe new questions that it has produced. Any exception to this structure must be approved in advance by the student’s dissertation advisory committee.

Procedures and requirements for the final dissertation manuscript are described in Dissertations.

Contact Info

Molecular and Cellular Biology Website

Lindsay Guest 
Graduate Program Administrator 
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