Drew E. Cressman

BA, Swarthmore College. PhD, University of Pennsylvania. Special interest in the molecular basis of gene regulation and the control of gene expression; specifically focused on the control of antigen-presenting genes of the immune system and the subcellular localization of the regulatory protein CIITA; author of papers on mammalian liver regeneration and CIITA activity; recipient of grants from the Irvington Institute for Biomedical Research and the National Science Foundation. SLC, 2000–

Undergraduate Courses 2020-2021

Biology

Advanced Cell Biology

Advanced , Seminar—Spring

The different kinds of cells in an organism—and the different ways that any cell can respond to changes in its environment—result from differences in the timing and level of expression of various genes that are responsible for their different cellular activity. Therefore, a fundamental question in biology is to understand the mechanisms used by cells to regulate gene expression and subsequent cell function. Most regulation of gene function occurs at the level of DNA activity (transcription), and it has been estimated that 10% of all human genes encode the transcription factors responsible for this level of regulation. Because of the complexity of the cell and the critical need to maintain normal cell function in a variety of environments, however, multiple mechanisms have evolved to modify and control cell activity. In this course, we will focus on these various mechanisms, examining regulatory events at the level of transcription, translation, receptor activity and signal transduction, determination of cell fate, and the modification and localization of intracellular proteins. Once we understand how cells regulate their function, we can begin to imagine ways in which we may intervene to modify specific cell activities, as well as how specific chemicals and compounds alter those regulatory mechanisms to the detriment of the cell.

Faculty

Human Genetics

Open , Lecture—Fall

The formation of an individual’s life is dependent upon a complex mixture of cultural experiences, social interactions, and personal health and physiology. At the center of this intricate web lies the biological components unique to each of us, yet shared in some form by all life on Earth—our genes. Genes contribute much to what makes each of us an individual, from hair color and body shape to intelligence and personality. Such genes and traits are inherited from our parents, yet environmental factors can profoundly influence their function in different individuals. Stunning advancements in the field of genetics are reported every day, from the identification of new genes for particular traits to the development of gene-based tests for human diseases. But what exactly are genes, and how do they work in humans? In this course, we will explore how genes and chromosomes provide the basic blueprint that leads to our unique physical and behavioral characteristics. In doing so, we will discuss the central concepts of human genetics, including: the mechanisms and patterns of inheritance, sex-linked traits, the genetics of behavior, DNA and proteins, the role of mutations in causing disease, human origins and evolution, and the application of various technologies such as gene therapy and genetic engineering. Readings will be drawn from texts, as well as from current popular-press and peer-reviewed articles. No previous background in biology is required other than a curiosity and desire to understand the genetic mechanisms that shape human existence and make us who we are.

Faculty

First-Year Studies: Conflicts in Biology

Open , FYS—Year

As the frontiers of science are pushed forward, conflicts naturally emerge between new hypotheses and established ideas. Biology is no exception to this rule. Since the time of the ancient Greeks, new proposals examining the biological nature of humans and the living world have initially met with resistance and even ridicule before becoming established as modern paradigms. What appears obvious now was once regarded as revolutionary, while it is conceivable that current ideas one day will be regarded as bordering on the absurd. Oftentimes, these conflicts arise not only due to the convergence of scientific principles but also result from personality clashes of the individuals involved in the research area. Paradigm shifts have occurred in a variety of biological fields, ranging from early ideas on heredity, sex determination, and evolution to more recent advances in prion and mad cow diseases, animal model usage, genetic engineering, cutting-edge cancer therapies, and the interplay between genes and environment. Using these and other examples, we will examine the progress of biological thought and the persistence of the scientific method in changing our understanding of life. During the fall semester, students will meet weekly with the instructor for individual conferences. In the spring, we will meet weekly or every other week, depending on students’ needs and the progress of their conference projects.

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Previous Courses

Forensic Biology

Open , Seminar—Spring

From hit television shows such as CSI, Bones, and Forensic Files to newspaper headlines that breathlessly relate the discovery of a murder victim’s remains...and to Casey Anthony, JonBenet Ramsey, and other real-life cases, it is clear that the world of forensic science has captured the public imagination. Forensic science describes the application of scientific knowledge to legal problems and encompasses an impressively wide variety of subdisciplines and areas of expertise, ranging from forensic anthropology to wildlife forensics. In this course, we will specifically focus on the realm of forensic biology—the generation and use of legally relevant information gleaned from the field of biology. In an effort to move beyond sensationalism and the way forensic biology is portrayed in the public media, we will explore the actual science and techniques that form the basis of forensic biology and seek to understand the use and limitations of such information in the legal sphere. Beginning with the historical development of forensic biology, selected topics will likely include death and stages of decomposition; determination of postmortem intervals; the role of microorganisms in decomposition; vertebrate and invertebrate scavenging; wound patterning; urban mummification; biological material collection and storage; victim and ancestral identification by genetic analysis; the use of DNA databases such as CODIS; and the biological basis of other criminalistics procedures, including fingerprinting and blood type analysis. Finally, we will consider DNA privacy and US Supreme Court rulings, including the 2013 decision Maryland v. King, which established the right of law enforcement to take DNA samples from individuals arrested for a crime. In all of these areas, the techniques and concepts employed are derived from some of the most fundamental principles and structure/function relationships that underlie the entire field of biology. No background in biology is required; indeed, a primary objective of this course is to use our exploration within the framework of forensic biology as a means to develop a broader and more thorough understanding of the science of biology.

Faculty

Virology

Advanced , Seminar—Spring

Viruses are some of the smallest biological entities found in nature—yet, at the same time, perhaps the most notorious. Having no independent metabolic activity of their own, they function as intracellular parasites, depending entirely upon infecting and interacting with the cells of a host organism to produce new copies of themselves. The effects on the host organism can be catastrophic, leading to disease and death. HIV has killed more than 39 million people since its identification and infected twice that number. Ebola, West Nile virus, herpes and pox viruses...are all well-known viruses yet shrouded in fear and mystery. During the course of this semester, we will examine the biology of viruses, discussing their physical and genetic properties, their interaction with host cells, their ability to commandeer the cellular machinery for their own reproductive needs, the effects of viral infection on host cells, and finally how viruses and other subviral entities may have originated and evolved. In addition, we will examine how viruses have been portrayed in literature, with readings that include Laurie Garrett’s The Coming Plague and Richard Preston’s The Hot Zone.

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Related Disciplines

Cell Biology

Intermediate , Seminar—Fall

Cells are the most basic unit of life on the planet. All life forms are simply conglomerations of cells, ranging from the individual bacterial cells to the higher order plants and animals. Humans, themselves, are made up of trillions of cells. So what exactly is a cell? What is it made of? How does it function? In a complex organism, how do cells communicate with one another and coordinate their activities? How do they regulate their growth? What role do genes play in controlling cellular function? This course will address these questions and introduce the basic biology of cells while keeping in mind their larger role in tissues and organs. If we can understand the structures and functions of the individual cells that serve as the subunits of larger organisms, we can begin to understand the biological nature of humans and other complex life forms.

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Related Disciplines

General Biology Series: Genes, Cells, and Evolution

Open , Lecture—Fall

Biology, the study of life on Earth, encompasses structures and forms ranging from the very minute to the very large. In order to grasp the complexities of life, we begin this study with the cellular and molecular forms and mechanisms that serve as the foundation for all living organisms. The initial part of the semester will introduce the fundamental molecules critical to the biochemistry of life processes. From there, we branch out to investigate the major ideas, structures, and concepts central to the biology of cells, genetics, and the chromosomal basis of inheritance. Finally, we conclude the semester by examining how those principles relate to the mechanisms of evolution. Throughout the semester, we will discuss the individuals responsible for major discoveries, as well as the experimental techniques and process by which such advances in biological understanding are made. Classes will be supplemented with weekly laboratory work.

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Related Disciplines

Biology of Cancer

Intermediate , Seminar—Fall

Cancer is likely the most feared and notorious of human diseases, being devastating in both its scope and its prognosis. Cancer has been described as an alien invader inside one’s own body, characterized by its insidious spread and devious ability to resist countermeasures. Cancer’s legendary status is rightfully earned, accounting for 13% of all human deaths worldwide and killing an estimated eight million people annually. In 1971, President Richard Nixon declared a “war on cancer”; since then, more than $200 billion has been spent on cancer research. While clinical success has been modest, tremendous insights have been generated in understanding the cellular, molecular, and genetic mechanisms of this disease. In this course, we will explore the field of cancer biology, covering topics such as tumor viruses, cellular oncogenes and tumor suppressor genes, cell immortalization, multistep tumorigenesis, cancer development and metastasis, and the treatment of cancer. In addition, we will discuss new advances in cancer research and draw from recent articles in the published literature.

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Related Disciplines

Forensic Biology

Open , Seminar—Spring

From hit television shows such as CSI, Bones, Dexter, and Forensic Files, to newspaper headlines that breathlessly relate the discovery of a murder victim’s remains, and to Casey Anthony, Amanda Knox, and other real-life courtroom cases, it is clear that the world of forensic science has captured the public's imagination. Forensic science describes the application of scientific knowledge to legal problems and encompasses an impressively wide variety of subdisciplines and areas of expertise, ranging from forensic anthropology to wildlife forensics. In this course, we will specifically focus on the realm of forensic biology—the generation and use of legally relevant information gleaned from the field of biology. In an effort to move beyond sensationalism and the way it is portrayed in the public media, we will explore the actual science and techniques that form the basis of forensic biology and seek to understand the use and limitations of such information in the legal sphere. Beginning with the historical development of forensic biology, selected topics will likely include death and stages of decomposition, determination of postmortem intervals, the role of microorganisms in decomposition, vertebrate and invertebrate scavenging, wound patterning, urban mummification, biological material collection and storage, victim and ancestral identification by genetic analysis, the use of DNA databases such as CODIS, and the biological basis of other criminalistics procedures, including fingerprinting and blood-type analysis. Finally, we will consider DNA privacy and Supreme Court rulings, including the Maryland v. King decision (2013) that established the right of law enforcement to take DNA samples from individuals arrested for a crime. In all of these areas, the techniques and concepts employed are derived from some of the most fundamental principles and structure-function relationships that underlie the entire field of biology. No background in biology is required; indeed, a primary objective of this course is to use our exploration within the framework of forensic biology as a means to develop a broader and more thorough understanding of the science of biology.

Faculty
Related Disciplines