Innovations in teaching undergraduate biology and why we need them.

A growing revolution is under way in the teaching of introductory science to undergraduates. It is driven by concerns about American competitiveness as well as results from recent educational research, which explains why traditional teaching approaches in large classes fail to reach many students and provides a basis for designing improved methods of instruction. Discipline-based educational research in the life sciences and other areas has identified several innovative promising practices and demonstrated their effectiveness for increasing student learning. Their widespread adoption could have a major impact on the introductory training of biology students.

Timing and mechanism of the initial cue establishing handed left­right asymmetry in Caenorhabditis elegans embryos.

By the six-cell stage, embryos of Caenorhabditis elegans are morphologically L­R asymmetric with an invariant handedness that persists throughout development. We used intracellular markers to ask whether breaking of L­R symmetry could be observed at earlier stages. Observation of two- to three-cell embryos carrying intracellular markers indicated that L­R symmetry is broken concomitantly with establishment of D­V axis polarity during division of the anterior AB cell. The AB cleavage furrow initiates asymmetrically and always from the left, suggesting L­R differences in the AB cell cortex. An invariantly handed cortical rotation observed earlier during first cleavage implies that the one-cell embryo has an intrinsic chirality. We propose that L­R differences in the cortex could result from mechanical forces on asymmetric components of a chiral cortical network during the off-axis elongation of the AB-cell spindle prior to AB cleavage.

A negative regulatory loop between microRNA and Hox gene controls posterior identities in Caenorhabditis elegans.

MicroRNAs (miRNAs) have been found to regulate gene expression across eukaryotic species, but the function of most miRNA genes remains unknown. Here we describe how the analysis of the expression patterns of a well-conserved miRNA gene, mir-57, at cellular resolution for every minute during early development of Caenorhabditis elegans provided key insights in understanding its function. Remarkably, mir-57 expression shows strong positional bias but little tissue specificity, a pattern reminiscent of Hox gene function. Despite the minor defects produced by a loss of function mutation, overexpression of mir-57 causes dramatic posterior defects, which also mimic the phenotypes of mutant alleles of a posterior Hox gene, nob-1, an Abd homolog. More importantly, nob-1 expression is found in the same two posterior AB sublineages as those expressing mir-57 but with an earlier onset. Intriguingly, nob-1 functions as an activator for mir-57 expression; it is also a direct target of mir-57. In agreement with this, loss of mir-57 function partially rescues the nob-1 allele defects, indicating a negative feedback regulatory loop between the miRNA and Hox gene to provide positional cues. Given the conservation of the miRNA and Hox gene, the regulatory mechanism might be broadly used across species. The strategy used here to explore mir-57 function provides a path to dissect the regulatory relationship between genes.

Learning and Doing: An Interview with Bill Wood.

THE Genetics Society of America's Elizabeth W. Jones Award for Excellence in Education recognizes significant and sustained impact on genetics education. As well as having made major contributions to biochemistry and developmental genetics, the 2016 awardee William B. Wood has been a pioneer in the reform of science teaching. Wood's leadership has been crucial in several national initiatives and programs, including the development of the influential National Academies Summer institutes on Undergraduate Education in Biology. He has also catalyzed change in education through his service as Editor-in-Chief of CBE-Life Sciences Education, a peer-reviewed journal published by the American Society for Cell Biology, in editorial partnership with the GSA.

Teaching Genetics: Past, Present, and Future.

Genetics teaching at the undergraduate level has changed in many ways over the past century. Compared to those of 100 years ago, contemporary genetics courses are broader in content and are taught increasingly differently, using instructional techniques based on educational research and constructed around the principles of active learning and backward design. Future courses can benefit from wider adoption of these approaches, more emphasis on the practice of genetics as a science, and new methods of assessing student learning.

A cuticle collagen encoded by the lon-3 gene may be a target of TGF-beta signaling in determining Caenorhabditis elegans body shape.

The signaling pathway initiated by the TGF-beta family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function (lf) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-beta signaling controls C. elegans body shape by regulating cuticle composition.

Teaching more by lecturing less.

We carried out an experiment to determine whether student learning gains in a large, traditionally taught, upper-division lecture course in developmental biology could be increased by partially changing to a more interactive classroom format. In two successive semesters, we presented the same course syllabus using different teaching styles: in fall 2003, the traditional lecture format; and in spring 2004, decreased lecturing and addition of student participation and cooperative problem solving during class time, including frequent in-class assessment of understanding. We used performance on pretests and posttests, and on homework problems to estimate and compare student learning gains between the two semesters. Our results indicated significantly higher learning gains and better conceptual understanding in the more interactive course. To assess reproducibility of these effects, we repeated the interactive course in spring 2005 with similar results. Our findings parallel results of similar teaching-style comparisons made in other disciplines. On the basis of this evidence, we propose a general model for teaching large biology courses that incorporates interactive engagement and cooperative work in place of some lecturing, while retaining course content by demanding greater student responsibility for learning outside of class.

The molecular biology capstone assessment: a concept assessment for upper-division molecular biology students.

Measuring students' conceptual understandings has become increasingly important to biology faculty members involved in evaluating and improving departmental programs. We developed the Molecular Biology Capstone Assessment (MBCA) to gauge comprehension of fundamental concepts in molecular and cell biology and the ability to apply these concepts in novel scenarios. Targeted at graduating students, the MBCA consists of 18 multiple-true/false (T/F) questions. Each question consists of a narrative stem followed by four T/F statements, which allows a more detailed assessment of student understanding than the traditional multiple-choice format. Questions were iteratively developed with extensive faculty and student feedback, including validation through faculty reviews and response validation through student interviews. The final assessment was taken online by 504 students in upper-division courses at seven institutions. Data from this administration indicate that the MBCA has acceptable levels of internal reliability (α=0.80) and test-retest stability (r=0.93). Students achieved a wide range of scores with a 67% overall average. Performance results suggest that students have an incomplete understanding of many molecular biology concepts and continue to hold incorrect conceptions previously documented among introductory-level students. By pinpointing areas of conceptual difficulty, the MBCA can provide faculty members with guidance for improving undergraduate biology programs.

Inquiry-based undergraduate teaching in the life sciences at large research universities: a perspective on the Boyer Commission Report.

The 1998 Boyer Commission Report advocated improvement of undergraduate education at large research universities through large-scale participation of undergraduates in the universities' research mission. At a recent conference sponsored by the Reinvention Center, which is dedicated to furthering the goals of the Boyer Commission, participants discussed progress toward these goals and recommendations for future action. A breakout group representing the life sciences concluded that independent research experience for every undergraduate may not be feasible or desirable but that transformation of lecture courses to more inquiry-based and interactive formats can effectively further the Commission's goals.

Advanced high school biology in an era of rapid change: a summary of the biology panel report from the NRC Committee on Programs for Advanced Study of Mathematics and Science in American High Schools.

A recently released National Research Council (NRC) report, Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools, evaluated and recommended changes in the Advanced Placement (AP), International Baccalaureate (IB), and other advanced secondary school science programs. As part of this study, discipline-specific panels were formed to evaluate advanced programs in biology, chemistry, physics, and mathematics. Among the conclusions of the Content Panel for Biology were that AP courses in particular suffer from inadequate quality control as well as excessive pressure to fulfill their advanced placement function, which encourages teachers to attempt coverage of all areas of biology and emphasize memorization of facts rather than in-depth understanding. In this essay, the Panel's principal findings are discussed, with an emphasis on its recommendation that colleges and universities should be strongly discouraged from using performance on either the AP examination or the IB examination as the sole basis for automatic placement out of required introductory courses for biology majors and distribution requirements for nonmajors.

What's Downstream? A Set of Classroom Exercises to Help Students Understand Recessive Epistasis.

Undergraduate students in genetics and developmental biology courses often struggle with the concept of epistasis because they are unaware that the logic of gene interactions differs between enzymatic pathways and signaling pathways. If students try to develop and memorize a single simple rule for predicting epistatic relationships without taking into account the nature of the pathway under consideration, they can become confused by cases where the rule does not apply. To remedy this problem, we developed a short pre-/post-test, an in-class activity for small groups, and a series of clicker questions about recessive epistasis in the context of a signaling pathway that intersects with an enzymatic pathway. We also developed a series of homework problems that provide deliberate practice in applying concepts in epistasis to different pathways and experimental situations. Students show significant improvement from pretest to posttest, and perform well on homework and exam questions following this activity. Here we describe these materials, as well as the formative and summative assessment results from one group of students to show how the activities impact student learning.

A diagnostic assessment for introductory molecular and cell biology.

We have developed and validated a tool for assessing understanding of a selection of fundamental concepts and basic knowledge in undergraduate introductory molecular and cell biology, focusing on areas in which students often have misconceptions. This multiple-choice Introductory Molecular and Cell Biology Assessment (IMCA) instrument is designed for use as a pre- and posttest to measure student learning gains. To develop the assessment, we first worked with faculty to create a set of learning goals that targeted important concepts in the field and seemed likely to be emphasized by most instructors teaching these subjects. We interviewed students using open-ended questions to identify commonly held misconceptions, formulated multiple-choice questions that included these ideas as distracters, and reinterviewed students to establish validity of the instrument. The assessment was then evaluated by 25 biology experts and modified based on their suggestions. The complete revised assessment was administered to more than 1300 students at three institutions. Analysis of statistical parameters including item difficulty, item discrimination, and reliability provides evidence that the IMCA is a valid and reliable instrument with several potential uses in gauging student learning of key concepts in molecular and cell biology.

The Genetics Concept Assessment: a new concept inventory for gauging student understanding of genetics.

We have designed, developed, and validated a 25-question Genetics Concept Assessment (GCA) to test achievement of nine broad learning goals in majors and nonmajors undergraduate genetics courses. Written in everyday language with minimal jargon, the GCA is intended for use as a pre- and posttest to measure student learning gains. The assessment was reviewed by genetics experts, validated by student interviews, and taken by >600 students at three institutions. Normalized learning gains on the GCA were positively correlated with averaged exam scores, suggesting that the GCA measures understanding of topics relevant to instructors. Statistical analysis of our results shows that differences in the item difficulty and item discrimination index values between different questions on pre- and posttests can be used to distinguish between concepts that are well or poorly learned during a course.