The central dogma of biology is a foundational concept that provides a scaffold to understand how genetic information flows in biological systems. Despite its importance, undergraduate students often poorly understand central dogma processes (DNA replication, transcription, and translation), how information is encoded and used in each of these processes, and the relationships between them. To help students overcome these conceptual difficulties, we designed a clicker-based activity focused on two brothers who have multiple nucleotide differences in their dystrophin gene sequence, resulting in one who has Duchenne muscular dystrophy (DMD) and one who does not. This activity asks students to predict the effects of various types of mutations on DNA replication, transcription, and translation. To determine the effectiveness of this activity, we taught it in ten large-enrollment courses at five different institutions and assessed its effect by evaluating student responses to pre/post short answer questions, clicker questions, and multiple-choice exam questions. Students showed learning gains from the pre to the post on the short answer questions and performed highly on end-of-unit exam questions targeting similar concepts. This activity can be presented at various points during the semester (e.g., when discussing the central dogma, mutations, or disease) and has been used successfully in a variety of courses ranging from non-majors introductory biology to advanced upper level biology.

The central dogma of biology is a foundational concept that provides a scaffold to understand how genetic information flows in biological systems. Despite its importance, undergraduate students often poorly understand central dogma processes (DNA replication, transcription, and translation), how information is encoded and used in each of these processes, and the relationships between them. To help students overcome these conceptual difficulties, we designed a clicker-based activity focused on two brothers who have multiple nucleotide differences in their dystrophin gene sequence, resulting in one who has Duchenne muscular dystrophy (DMD) and one who does not. This activity asks students to predict the effects of various types of mutations on DNA replication, transcription, and translation. To determine the effectiveness of this activity, we taught it in ten large-enrollment courses at five different institutions and assessed its effect by evaluating student responses to pre/post short answer questions, clicker questions, and multiple-choice exam questions. Students showed learning gains from the pre to the post on the short answer questions and performed highly on end-of-unit exam questions targeting similar concepts. This activity can be presented at various points during the semester (e.g., when discussing the central dogma, mutations, or disease) and has been used successfully in a variety of courses ranging from non-majors introductory biology to advanced upper level biology.

Mutations in genes can lead to a variety of phenotypes, including various human diseases. Students often understand that a particular mutation in a single gene causes a disease phenotype, but it is more challenging to illustrate complex genetic concepts such as that similar mutations in the same gene cause very different phenotypes or that mutations in different genes cause similar phenotypes. We originally designed this lesson to build off of the CourseSource lesson “A clicker-based case study that untangles student thinking about the processes in the central dogma,” but it can also stand alone. In our lesson, students read or listen to a real-life case study featuring a patient who doggedly pursues the underlying genetic cause of her own disease—muscular dystrophy—and stumbles upon a similar mutation in the same gene that gives an athlete the seemingly opposite phenotype: pronounced muscles. The lesson also leads the students to overlay their understanding of the central dogma and mutation on protein function and disease, compares muscular dystrophy to the disease progeria, and concludes with an ethical challenge. We tested the lesson as both an independent homework assignment, as well as a small group in-class worksheet and both formats were successful.

Primary Image: Line drawing of a space filling diagram of the LMNA protein illustrating mutations that lead to progeria.

Our understanding of microbiomes, or the collection of microorganisms and their genes in a given environment, has been revolutionized by technological and computational advances. However, many undergraduate students do not get hands-on experiences with processing, analyzing, or interpreting these types of datasets. Recent global events have increased the need for effective educational activities that can be performed virtually and remotely. Here, we present a module that introduces STEM undergraduates to the bioinformatic and statistical analyses of bacterial communities using a combination of free, web-based data processing software. These lessons allow students to engage with the studies of microbiomes; gain valuable experiences processing large, high-throughput datasets; and practice their science communication skills. The lessons presented here walk students through two web-based platforms. The first (DNA Subway) is an easy-to-use wrapper of the popular QIIME (pronounced “chime”) pipeline, which performs quality control analysis of the raw sequence data and outputs a community matrix file with assigned bacterial taxonomies. The second, ranacapa, is an R Shiny App that allows students to compare microbial communities, perform statistical analyses and visualize community data. Students may communicate their findings with a written final report or oral presentation. While the lessons presented here use a sample dataset based on the gut-microbiome of the bean beetle (Callosobruchus maculatus), the materials are easily modified to use original next-generation amplicon sequence data from any host or environment. Additionally, options for alternative datasets are also provided facilitating flexibility within the curriculum.

Primary Image: Insects are an excellent example of a tractable biological system to study the relationship between an organism and its microbiome. Little is currently known about the gut-microbiome of many insects, such as the bean beetle (Callosobruchus maculatus).

To facilitate understanding of the fundamental genetic concept of the genotype-phenotype relationship in our introductory biology students, we designed an engaging multi-week series of related lessons about canine genetics in which students explore and answer the question, "How does the information encoded in DNA lead to physical traits in an organism?" Dogs are an excellent model organism for students since the genetic basis for complex morphological traits of various breeds is an active area of scientific research and dog DNA is easily accessible. Additionally, examination of students' pets offers a relatable, real-world, connection for students. Of the more than 19,000 genes that control canine genetics, simple genetic mutations in three genes are largely responsible for the coat variations of dogs –specifically, the genes that control hair length, curl, and the presence/absence of furnishings. In our lessons, students collect DNA samples from dogs, isolate and amplify targeted sections of DNA through polymerase chain reactions (PCR), and then sequence and analyze DNA for insertions and single nucleotide polymorphism (SNP) mutations. Utilizing gel electrophoresis and bioinformatics tools, students connect how the physical manifestation of traits is rooted in genetic sequences. Students also participate in discussions of scientific literature, group collaboration to construct a final poster, and presentation of their findings during a mock scientific poster conference. Through this module students engage in progressive exploration of genetic and molecular techniques that reveal how simple variations in a few DNA sequences in combination lead to a broad diversity of coat quality in domestic dog breeds.

Primary image. Genetic Analysis of Canine Coat Morphologies. Three dogs with differing coat morphologies analyzed by students (A, B, C), an agarose gel post-electrophoresis (D), and a chromatogram of a DNA sequence highlighting a relevant mutation (E). This collage contains original images taken by authors and course participants.