Using DNA to Teach the History and Nature of Science

Author: Kevin Bonney

Liberal Studies courses provide many opportunities to illustrate the dynamic and collaborative nature of science and examine connections between science and other disciplines. For example, teaching the history and ethical implications of science in addition to basic science concepts can enrich understanding of contemporary issues and events and help students learn to apply prior knowledge in future scenarios. One topic in Life Science for which this is especially germane is the structure of DNA, and the story of its discovery.

Although many students can identify James Watson and Francis Crick as discoverers of the double-helix structure of DNA, they may not appreciate that this Nobel Prize-winning discovery would not have been possible without knowledge gleaned from decades of work by other scientists. Most notable is the case of Rosalind Franklin who provided critical data and insight that Watson and Crick used in constructing their model, yet, many argue, faced discrimination as a woman scientist and was not appropriately acknowledged for her contributions to the field. The intertwined narratives of Watson, Crick, and Franklin form just one plot line in the complex story of DNA.  Beginning with the characterization of DNA by Friedrich Miescher in 1869, numerous scientists including Nikolai Koltsov, Fred Griffith, Oswald Avery, Colin MacLeod, Macyln McCarty, Erwin Chargaff, Maurice Wilkins, Alfred Hershey, Martha Chase, Linus Pauling, and Robert Corey helped develop the rich narrative of DNA. One could logically choose 1958, when Matthew Meselson and Frank Stahl demonstrated the semi-conservative model of DNA replication, as an end point for the timeline of DNA history. However, more recent chapters leading to contemporary technologies such as genetic engineering and forensic DNA science are perhaps the most exciting and relatable.

Class activities that promote learning about the history of DNA, such as creating timelines, discussing primary literature, and engaging in debates about the significance and implications of different discoveries can be easily completed in most educational settings with the help of freely available instructional resources. A sampling of open educational resources that facilitate learning about DNA is described in Table 1. In addition to engaging activities, many of these resources include formative and summative assessments that can be used as is or modified to better meet instructional needs.

One effective use of these resources begins with directing groups of three to four students to construct a timeline of important experimental findings using information provided on the Cold Spring Harbor DNA Interactive website (Table 1). Following this activity, each student is assigned one individual or team of scientists to research further using the Cold Spring Harbor, Public Broadcasting Service (PBS), and the National Center for Case Study Teaching in Science (NCCSTS) resources (Table 1). Synthesis of a two page essay and/or five to ten minute presentation on the life and discoveries of the chosen scientists is then used to promote development research, writing, and presentation skills, and facilitate discussion about how the contributions of each scientist are interconnected.  In the following class period students collaborate on the “Base pairing interactive” on the DNA Interactive website and the 3D DNA Explorer tool provided by the PBS DNA (Table 1). These modules engage students in actively piecing together DNA base pairs and investigating a three-dimensional DNA double helix from multiple angles.

An alternative approach for promoting class discussion and reflective writing is the use of case studies. Both case studies described in Table 1 present information about the key experiments in the form of a narrative that is interrupted by questions to promote analytical thinking and group discussion.  These case studies are best completed in small groups over two to three class periods, but could be completed individually, or in larger groups. It is not necessary to complete every part of the case studies to facilitate coherent and meaningful instruction. Between each part of the case, it is important to regroup to discuss the answers and reasoning for the questions that have been completed. Responses to questions in the case study are best evaluated as part of a low-stakes, formative assessment, followed by group discussion of the responses. Summative assessments can include similar but varied questions to those in the case study.

In addition to their applicability in a variety of science courses, these activities could be incorporated into history or writing courses to promote interdisciplinary learning and emphasize the role of science in society. Regardless of the extent to which resources such as those described here are utilized, it is important to provide students a well-rounded education that provides both the context and the rationale for concepts and methodologies, rather than facts alone.

Table 1. Suggested Resources for Teaching About the Discovery of DNA.