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Doctor of Philosophy (Ph.D.) in Microbiology

The degree of Doctor of Philosophy is granted for proven ability, independent investigation, and scholarly attainment in a special field. Although it is primarily a research degree and is not granted solely on the completion of a certain number of credits, there are specific course requirements that must be met. The training of a Ph.D.-level Microbiologist is based on a strong foundation in Mathematics, Chemistry, Genetics, Molecular Biology, and Biochemistry in addition to extensive coursework in the various disciplines within the field of Microbiology. This base is built upon advanced course work in the major sub-disciplines of Microbiology (Molecular Biology, Biochemistry and Physiology, Genetics, Biotechnology, Virology, Industrial and Environmental Microbiology, and Medical Microbiology) as the student focuses his/her area of interest.


Admission Requirements

Application to the Ph.D. program in Microbiology requires:

  1. A suitable faculty advisor from the Department of Biological Sciences.
  2. At least a 3.0 grade point average (GPA) for all upper-division credits taken in the previous degree program,
  3. Scores in the 40th percentile or higher on the verbal and quantitative sections of the Graduate Record Exam (GRE),
  4. Completed application to the Graduate School and Department of Biological Sciences, including three letters of recommendation.

Scores in the verbal, quantitative, and analytical sections of the GRE must be submitted before entrance can be considered. International students may be accepted without GRE scores, with the requirement that they take the GRE during their first semester in residence. Individuals for whom English is a second language must meet the Graduate School's minimal TOEFL score.

Applicants who do not meet the minimum GPA and/or GRE requirements may be admitted under "Classified (with performance requirements, w/PR)" status. The conditions of acceptance will be specified on the applicant's Approval for Admission to Graduate School form. In some cases, students may be required to retake the GRE during their first semester in residence. Students admitted under "Classified (w/PR)" status because of low/missing GRE scores will be transferred to "Classified" status if new GRE scores that meet the minimal requirement are submitted. Failure to meet the minimum GRE standards during the first year of residence may result in expulsion from the program. Students under "Classified (w/PR)" status must petition the Graduate Programs Committee for transfer to "Classified" status after a year of graduate work and successful remediation of any deficiencies in coursework or GRE scores. This petition will include a recommendation from the student's Advisory Committee signed by the research advisor. Continuation in the Microbiology Ph.D. program is contingent upon approval of transfer to "Classified" status. In rare cases, the Graduate Programs Committee may grant approval for a student to remain on "Classified (w/PR)" status for a second year. Any student with "Classified (w/PR)" status who has not been approved for transfer to "Classified" status by the end of his/her second year will be dismissed from the program. Acceptance into the Microbiology Ph.D. program must be approved by the Graduate Program Committee.

For applicants who hold only a Bachelor's degree, acceptance into the Microbiology Ph.D. program requires a minimum of a 3.0 GPA for all undergraduate work, scores in the 50th percentile or higher on the verbal and quantitative sections of the GRE. No waiver of GRE scores is allowed except in the case of students for whom English is a second language who receive a lower verbal GRE score; these individuals must meet the Graduate School minimal TOEFL score. The application must include three letters of recommendation. The application must be approved by the Departmental Graduate Program Committee.

Students in the Microbiology or Biology M.S. program may be permitted to change to the Microbiology Ph.D. program with approval of the Graduate Program Committee. Application for change must include:

  1. A letter from the student that provides a rationale for the status change and
  2. A letter of support from the research advisor.



The following courses are recommended for the Microbiology Ph.D. program. It is expected that applicants to the program will have a broad background in Biology and will have completed coursework at the undergraduate level in the following areas:

  • 1 semester of Calculus (Calculus through Multivariable Calculus recommended)
  • 1 year of General Chemistry
  • 1 year of Organic Chemistry
  • 1 year of Physics
  • 1 semester of Quantitative Analysis, Analytical Chemistry, or Inorganic Chemistry
  • 1 semester of Statistics or equivalent
  • Genetics
  • General Microbiology

The Microbiology Ph.D. program will be tailored to the requirements of the student's program of study (as determined by the student's Advisory Committee), and will include coursework to rectify any deficiencies as determined by the Graduate Program Committee. Deficiencies will be made up in the first year of study.


Graduate Coursework in the Microbiology Ph.D. program

The intent of the Microbiology Ph.D. program is to produce scientists with a broad background in the major sub-disciplines of Microbiology, while ensuring focused study in their major field of interest. The student's Graduate Advisory Committee will direct the student to specific course offerings within the Department and University to satisfy coursework guidelines. The three core areas in the Microbiology Ph.D. program are:

  • Biochemistry, Genetics, Molecular Biology, and Physiology of Microorganisms
  • Immunology, Virology, and Medical Microbiology
  • Microbial Ecology and Applied, Industrial, and Environmental Microbiology

Students in the Microbiology Ph.D. program will take at least 42 credits of formal graduate coursework (at least 15 credits will be at the 6600-level).

Course number

Course title


BIOL 6690

Careers in Life Sciences (fall semester of the first year)


BIOL 6605



BIOL 6691

Seminar (proposal, third semester)


BIOL 6648

Graduate Problems


BIOL 6695

Seminar in Microbiology (may be repeated up to 6 credits)


BIOL 8850

Doctoral Dissertation


Other course work      To be determined by committee approval


* Candidates who have already received an M.S. degree may transfer 9 credits of graduate-level work, providing grades of "B" or higher were earned. Transfer of credit is subject to approval by the Graduate Programs Committee.


Incoming Ph.D. students are required to take a diagnostic assessment to evaluate the breadth of their knowledge within multiple biological science disciplines and to help plan their Program of Study. The diagnostic assessment must be completed in the student's first semester as part of BIOL 6690.



Residency Requirements

The equivalent of at least four years of full-time study (minimum of 75 graduate credits) is required and the research upon which it is based should compose a substantial portion of the program and involve original work. Part of the work may be completed elsewhere with the approval of a student's Advisory Committee, but two consecutive regular semesters of full-time study must be taken in residence at this university.


Advisory Committee

The student's Advisory Committee will consist of the graduate research advisor and (at least) three additional members of the graduate faculty who are chosen by the student in consultation with the research advisor. It is the student's responsibility to contact members of the faculty to ascertain their willingness to serve. The Advisory Committee may include individuals from other departments or persons from outside the University who hold affiliate rank in the Department, with the approval of the Dean of the Graduate School, but the majority of any committee must consist of regular departmental faculty.

The final member of the student's Advisory Committee is a Graduate Faculty Representative (GFR) from outside the Department who is appointed by the Dean of the Graduate School. The Dean will automatically appoint a GFR to participate in the defense of the dissertation if one has not been appointed before that time. However, it has been traditional for the GFR to be an active member of the Advisory Committee who participated in committee meetings and the Comprehensive Examination. In such cases, the student must submit a request in writing to the Dean of the Graduate School that a particular individual be appointed. The GFR must be a member of the Graduate Faculty of Idaho State University.


Comprehensive Examination and Research Proposal Seminar

Before submission of the final program of study, the student must pass a Comprehensive Examination intended to test his/her knowledge of the relevant sub-disciplines within the field of Microbiology that pertain to the dissertation research project(s). The student will be admitted to this examination when the student is considered by his/her Advisory Committee to be adequately prepared. This is to be interpreted as allowing the student to take the Comprehensive Exam, even though some courses remain to be taken for the completion of the student's program of study.

The Comprehensive Examination should be taken following the 2nd semester (or equivalent) of residence in the Microbiology Ph.D. program, and prior to the end of the student's 5th semester (or equivalent) in the program. Several months (3 to 6) prior to the intended date for examination, the student should meet with his/her Advisory Committee to seek approval to schedule the exam. If approval is given, the student may at that time ascertain from the committee which topical areas will be covered and which committee member will be responsible for each. Students should meet individually with committee members to determine more specifically what materials will be pertinent and how to prepare for the exam. The examination will consist of a written and an oral portion, which will be administered during a closed session following the student's public Research Proposal Seminar. Both portions must be passed satisfactorily in order to complete the comprehensive requirements.

The written portion of the Comprehensive Exam should not be less than 25 hours nor more than 40 hours of actual writing time. Normally the written exams will be completed within the span of one week. The written portion of the Comprehensive Examination generally will involve the student applying the knowledge gained through graduate coursework and readings suggested by the Advisory Committee. The examination will consist of five sections, each meant to be answered by a five-hour essay. The specific topic areas covered will be determined by the student's Advisory Committee. Grading on the written portion will be on a Pass/Fail basis with four of the five sections graded satisfactory required for a Pass. If the student fails two or more sections of the written portion of the exam, the student's Advisory Committee will convene to determine if the student will be allowed to remain in the program. The student's Advisory Committee may recommend one of three options:

  • dismissal from the program;
  • transfer from the Microbiology Ph.D. program to the Microbiology M.S. program; or
  • re-examination of the failed sections of the written exam.

Failed sections may be repeated once, at a time designated by the student's Advisory Committee, but within a year of the original examination. If a student has not passed all the written sections after repeating the failed sections once, that student will be dismissed from the program. The completed and graded written portion of the Comprehensive Exam is to be deposited in the student's department file.

Students pursuing the Microbiology Ph.D. are required to present a Seminar based on their Research Proposal to the Department of Biological Sciences prior to the end of their 5th semester (or equivalent) in the program. The seminar will be given during a scheduled meeting time of the Graduate Seminar in Microbiology (BIOL 6695) and will be considered part of the course requirements for that student. The purpose of the Research Proposal Seminar is to assess the student's potential for graduate study at the doctoral level, to determine areas in which the student shows strength or weakness, and to assess the student's ability to assimilate, evaluate, and synthesize subject matter. Immediately after the seminar, the student will meet in closed session with his/her Advisory Committee to review and critique the Research Proposal Seminar and the written portion of the Comprehensive Exam. This meeting will qualify as the oral portion of the Comprehensive Exam.

The purpose of the oral portion of the examination following the Research Proposal Seminar is to provide an opportunity to clarify and explore further implications of the written examination as well as to present the student with new questions in the same general subject areas as those covered by the written exams, but it can also cover other areas that are relevant to the student's graduate program. The oral portions should not be given until after the written examination has been evaluated by all of the committee members, but no later than four weeks after completion of the written portion. The student must pass the written portion of the Comprehensive Exam prior to taking the oral portion of the Comprehensive Exam. The oral exam must be passed by simple majority vote of the Advisory Committee. Once a student has passed both the written and oral portions of the Comprehensive Exam, the student will be admitted to Candidacy in the Microbiology Ph.D. program. When the student has passed both written and oral portions of the Comprehensive Exam, the Advisory Committee should finalize and approve the student's Final Program o f Study. The Advisory Committee may recommend additional coursework to strengthen the student's background in areas in which the student was considered weak. In case of failure, the student may be allowed to retake all or part of the oral examination at the discretion of his/her Advisory Committee. If a student fails the oral exam a second time, that student will be dismissed from the program.


Doctoral Dissertation

Every student working toward the Microbiology Ph.D. degree must submit a dissertation embodying the results of original and creative research.

The dissertation must demonstrate the student's ability in independent investigation and must be a contribution to scientific knowledge. It must display mastery of the literature of the subject field and must demonstrate an organized, coherent development of ideas, with a clear exposition of results and a creative discussion of the conclusions. Students may register for dissertation credit only after completion of all formal course work. After the dissertation, in substantially final form, has been approved for format and content by the research advisor, and not later than two weeks before the date of the final examination, the student must personally deliver a copy of the dissertation to each member of the Advisory Committee.

Please refer to the manual, Instructions for Preparing Theses, Dissertations, Doctor of Arts Papers, and Professional Projects, for thesis clearance instructions.


Final Examination

The final examination of the dissertation will be conducted by the student's Advisory Committee including the GFR. Students are required to give a departmental seminar on the dissertation immediately preceding the final examination. The examination is concerned primarily with the student's research as embodied in the dissertation, but it may be broader and extend over fields of study related to the dissertation. Questions may be asked by committee members and those visitors specifically invited to do so by mutual agreement of the student's Advisory Committee and the Dean of the Graduate School. A majority of the examining committee must approve the dissertation and the final examination