Comparing outdated and updated textbook figures helps introduce undergraduates to primary literature.

INTRODUCTION

Didactic tools such as textbooks collect and synthesize many research findings in order to present students with a field’s current understanding of a subject. But even the most authoritative textbook quickly becomes out of date. Our understanding of the natural world is always being refined. This is particularly evident in fast-paced fields such as genetics, where new technologies and methods lead to powerful new findings and radical changes in how we view inheritance, disease, and their molecular determinants. It is important that we introduce students to a particular field not only as a collection of facts but also as an active area of hypothesis-driven research and experimentation. These activities lead to a rapid evolution of our knowledge, which is most accurately reflected in primary literature.

In the context of the undergraduate classroom, we have used side-by-side comparison of old and updated textbook figures to introduce students to the field as a dynamic area of scientific inquiry. We also use this exercise as an opportunity to introduce students to relevant primary literature. We find that this is an effective way to transition students (at both the 200 and 300 level) from their textbook to primary literature as a source of information and to generate class discussion throughout the semester.

PROCEDURE

Students were shown pairs of corresponding figures from the 1st edition (9) and 5th edition (10) of Pierce’s Genetics: A Conceptual Approach textbook, the latter being the course’s required textbook. Figures were chosen based on changes observed in the figures, the relevance of the topic to the courses, and the impact on scientific thinking. Students were asked to determine differences between the two images.

After reading the assigned section and discussing in class the topic and differences between the figures, students in the 200-level class (17 students) were given a scientific manuscript which had led to the figure’s modification (6). Students read the manuscript before the next class, summarized the manuscript’s main findings, and listed any confusing topics and techniques. Students shared their summaries, and the class developed one summary statement of the manuscript. A discussion of the manuscript was then moderated by the instructor, focusing on the specific experiments and methodologies (particularly those new to the students) that had led to the figure’s evolution.

Alternatively, students in the 300-level Genetics class (two sections of 11 students), after having been assigned to read the textbook chapter containing the figure to be discussed, were instructed to search online for the scientific manuscript which had led to the figure changes. These students were also asked to articulate in a few words the reasoning behind their paper selections in an e-mail to the instructor that included a copy of or link to their paper selection. The instructor compiled all of the paper references received from students, as well as their abstracts. During the next class period, the instructor distributed this reference/abstract list to all students and moderated a discussion of the content of the submitted papers and their place in the research area in focus, with each student serving as an expert on the paper he or she had submitted. Based on this discussion, the class developed annotations for each reference.

At the end of both courses, students were asked to reflect on what they liked, what they disliked, and what they learned from these exercises (Appendix 1).

DISCUSSION

Side-by-side comparison of original and updated textbook figures proved to be a very effective method of raising students’ awareness about the dynamic changes within scientific fields. Students see how findings reported in primary scientific literature can refine textbook content, leading to a more complete understanding of a particular phenomenon. Because students were not expected to be familiar with all experimental techniques used, this method also effectively introduced students to such protocols. While this exercise was used several times during the course with different pairs of figures, we describe below one example in which the side-by-side comparison of a set of figures (Fig. 1) allowed students to observe the discovery and characterization of the RNA polymerase omega subunit.

FIGURE 1.

One of the pairs of figures examined by students. Diagrams showing the subunit composition of bacterial RNA Polymerase. Diagrams modeled after Figure 13.10 (A) and 13.9 (B) in the first and fifth editions of Pierce’s Genetics, respectively.

In the 200-level course, students were given a manuscript describing the function of the omega subunit of the Mycobacterium RNA polymerase holoenzyme (6). Although students understood that the paper depicted the omega subunit’s function, they experienced some difficulty interpreting each figure and relating the experiments to the conclusions (Appendix 1). Discussion revealed students’ interest in the relationship between the omega subunit and eukaryotic RNA polymerase enzymes. This led to investigation of an additional manuscript comparing prokaryotic and eukaryotic RNA polymerase protein complexes (7).

For the 300-level Genetics course, students were able to identify the paper that first reported the omega subunit associating with E. coli RNA polymerase (1). Students were also able to recognize a series of papers that assessed whether or not the omega subunit was a component of the RNA polymerase complex and sought to identify its function (2–4, 8). Students realized that, at the time when the first edition of the textbook was published (9), the field had not yet reached a consensus about the omega subunit being part of the RNA polymerase holoenzyme (5). Students were able to find and examine a collection of primary manuscripts to understand the discovery of the omega subunit as a functional RNA polymerase holoenzyme component.

Students’ familiarity with primary literature, search engines like Pubmed, and scientific citation indexing services like Web of Science facilitated the implementation of this activity in the classroom (Appendix 1). This exercise could be improved by providing figures without access to references and by allowing students to orally present figures within the manuscripts to enhance class discussion.

In conclusion, we recommend this method of introducing undergraduate students to primary literature in a way that transitions smoothly from their more traditional, textbook-driven background. We find that the activity builds students’ confidence in their ability to find scientific papers of interest. In addition, this process encourages them to appreciate the biological sciences not as a completed story, but rather as an active area of scientific inquiry.

Appendix 1: Table 1: Student responses to reflection questions