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This interactive case discussion was created to emphasize the clinical relevance of population genetics, but is also a suitable resource for teaching the basic principles of population genetics while relating them to human genetic variation. Our understanding of human genetic variation has deepened over the past decade due to fine-scale genome mapping. Applying this knowledge to the evaluation of ancestry-based genetic testing strategies, such as direct-to-consumer genetic testing, is an important component of the practice of culturally-competent medicine and a relevant way to teach the foundations of population genetics, including Hardy-Weinberg equilibrium.

This interrupted case is based on a genome wide association study (GWAS) that identified the genetic variation causing some inhabitants of the Solomon Islands to have blond hair. The case illustrates the connection between genotype and phenotype, and an application of Hardy-Weinberg equilibrium. The narrative focusses on John and his new roommate, Peter, from the Solomon Islands who happens to have dark skin and blond hair. Using thought-provoking questions students learn about the genetics and the biochemistry of the hair color trait and how a single genetic variation can influence phenotype. Is migration or mutation involved?  Upon completion of the activity students will know the source of the genetic variation that causes the blond hair phenomenon in the Solomon Islands and if it has any European origins. The case was written for an upper-level genetics course, but could also be adapted for introductory biology or for a genetics course for non-majors. An optional PowerPoint presentation with clicker questions is available for download from within the Answer Key.

This interrupted case study for the flipped classroom applies evolutionary genetics research to human health. Students learn about a naturally occurring, but rare, allele of the CCR5 gene, CCR5-Δ32, which provides resistance to HIV. They use data from primary literature sources to predict and interpret worldwide patterns of CCR5-Δ32 frequency distribution. They then discuss how these allele frequency patterns may have been driven by selection imposed by various diseases or by other evolutionary mechanisms. Next, they test published data using Hardy-Weinberg equilibrium to examine if CCR5-Δ32 also provides genetic resistance to West Nile virus. Finally, they complete a jigsaw discussion of Nature News articles that report on how CCR5 research is being used to develop therapies to treat HIV. Originally written for the evolution portion of a yearlong biology series for undergraduate majors, the case is also appropriate for some non-majors biology courses or, with added complexity, upper-level evolution, genetics, or cell biology courses.

The protagonist of this two-day flipped case study, "Maria," has two problems. She doesn't like it when the apple slices in her lunch turn brown, and she needs to find a project for her biology class that includes molecular biology, preferably one that incorporates plants. Students are enlisted to help Maria understand Arctic Apples™, which don't turn brown because they have been genetically modified to suppress the expression of polyphenol oxidase via RNAi. The case also explores the health, environmental, and safety aspects of growing and eating plants that have been genetically modified to use RNAi. The case applies the central dogma of biology to the creation of genetically modified foods and RNAi and includes a discussion of whether genetically modified foods should be labeled. Several videos are included with the case, including one created by the author specifically for the case. The case is appropriate for use in an introductory level biology or survey level biochemistry course.

This directed case study was developed in order to present genomic data to students, allow them to interpret the impact of genetic variations on phenotype, and to explore precision medicine. Students are introduced to "Josie," a college sophomore who decides to have her genome sequenced after learning about genome-wide association studies (GWAS) in class. As students work  through the case, they learn about the different technologies that can be used in GWAS studies and interpret Josie's results for a subset of genetic markers that affect a range of traits from pharmacogenetics to disease risk alleles and non-pathogenic traits. Students are confronted with ethical issues such as duty to inform, actionable results, and variants of unknown significance (VUS). Students are also asked to reflect on their feelings about getting genomic testing for themselves. An optional activity for advanced students (included in the teaching notes) involves using the Gene database at NCBI to explore variants of the CYP2C9 gene. The case study is appropriate for use in undergraduate genetics or molecular biology classrooms.

This hands-on activity, used in conjunction with the film The Making of the Fittest: Natural Selection in Humans, teaches students about population genetics, the Hardy-Weinberg principle, and how natural selection alters the frequency distribution of heritable traits. It uses simple simulations to illustrate these complex concepts and includes exercises such as calculating allele and genotype frequencies, graphing and interpretation of data, and designing experiments to reinforce key concepts in population genetics.

 Students must consider the role of rumen bacteria and how genetic modification may alter the potential of these bacteria. The case engages students in learning basic principles of bacterial genetics and biotechnology as they consider how microbes and microbial processes impact the environment. The case could also be used in an introductory genetics or biotechnology course.

This directed case study follows the story of "Pauline," a 20-year-old college student who has just received results from a personal genetic testing kit she purchased online. The report shows a negative result for variants of the BRCA 1 and 2 genes, which are associated with a greater risk for breast cancer. Although Pauline has a family history of breast cancer, she concludes that she no longer needs to be concerned, or does she? As students work through the questions in this case study, they review the role of genes and how they code for proteins as well as the effects of proteins on health, especially on cellular growth regulation and cancer. They also learn about the process of genetic testing and consider the ramifications of positive and negative tests for diseases or health conditions, especially with respect to breast cancer. The case is designed for non-science majors in a scientific methods course and could also be used in an introductory biology course. The questions in the case could be adapted for an upper level genetics class.

This case study is centered on a real scenario from 2013 in which the Kickstarter fundraising platform included a fundraising proposal from a group wanting to use synthetic biology to make glowing plants. The proposal raised controversy because the Glowing Plant group offered to give away their genetically-modified glowing plant product to investors.  Kickstarter subsequently changed its policy to prevent use of genetically modified organisms as rewards or incentives to investors. This case study was developed for a college first-year seminar focused on the ethics of synthetic biology, and was introduced during the first week of the semester. The case uses the jigsaw teaching method to introduce students both to the mechanics of synthetic biology and to questions about how we should distribute the benefits and burdens associated with new or emerging technologies. It could be adapted for courses in introductory college biology, genetics or bioethics.

This case study was developed to teach the topic of human ABO blood type and genetic inheritance in biology courses at the lower undergraduate level or upper high school level. It is suitable for entry level biology, genetics, and physiology courses. The case narrative tells the story of Kevin, a teenager who is puzzled by the fact that neither of his parents can donate blood to him. He and his best friend ask their biology teacher for help, and she explains human ABO blood types at the molecular and genetic level to solve the mystery. The case consists of three sections, which can be used sequentially or separately. After completing the case study, students will understand the molecular basis of ABO blood types and how genes control the phenotype and genotype of an individual. They will also have a better understanding of how human ABO blood type is inherited from generation to generation.

In this case, developed for an introductory genetics class, students meet a woman whose family has a history of colon cancer. Students create a pedigree based on information from the case and discuss what it means to be genetically predisposed to cancer. Using bioinformatics tools from the NCBI database, students identify and examine the mutation in the woman's APC gene that results in genetic predisposition to colon cancer. Finally, they investigate the biological function of the APC protein to understand why this mutation contributes to the development of cancer and determine whether APC is a proto-oncogene, tumor suppressor gene, or genome stability gene.

This case study details the historical discovery of the structure of DNA. Images of this key molecule are as iconic as those of the Mona Lisa, and identifying its structure has proven to be as intriguing a mystery for scientists as the reason behind Mona Lisa's smile has been for art historians. The case is woven together by a series of fictional diary entries that detail the history of the discovery of DNA's structure, the major players involved, their ethical dilemmas, and the role of women in science. The case is designed for a high school course or introductory undergraduate genetics/ biochemistry courses. It can also be used as an interdisciplinary case study bridging genetics, bioethics, art, and the status of women in science. Designed as an interrupted case, it may be used in its entirety or in parts that pertain to a particular topic or discipline. No prior knowledge of genetics is required.

This case study is designed to teach basic concepts of genetics by focusing on a rare disease, pseudoxanthoma elasticum (PXE).  Chromosome 16 is the narrator at the beginning of the case and introduces students to genes, chromosomes and mutations. The focus then shifts to the patient and his mother as she finds out about her son's disease and her subsequent efforts to connect with patient advocacy groups for support. The case concludes with students watching a TED talk given by Sharon Terry, the real-life mother on whom this story is loosely based, so that students can connect on an emotional and human level with someone who has intimate experience as a parent of children with a rare genetic disease. The case is suitable for high school general biology classes, but it can also be used by biology major or non-major undergraduates in a lower-division biology class, or in any lower-division non-major class focused on human disease.

This PowerPoint-driven, flipped case study begins with a short video about a woman suffering from cystic fibrosis (CF) in the 1970s, a friend of the lead author's, whom she met in college and who died in her twenties. Hooked by this personal story, students then delve into the genetics and biology of cystic fibrosis as they learn about the difference between dominant and recessive genes, make Punnett squares that depict various types of inheritance, distinguish between probability and actual numbers, differentiate types of mutations, and learn about the opportunistic infections that CF patients often succumb to.  Students conclude the case by watching two additional videos on chest compression machines and the contemporary life expectancy of patients with CF.  In addition to the scientific content presented in the case, it is hoped that students will empathize with, and be motivated by, the young people presented in the videos as they struggle with a very real, incurable disease deeply rooted in genetics.

This case study presents the story of Phil, an undergraduate majoring in biology, whose Russian cousin Dimitri has contracted tuberculosis (TB) from inmates at the prison where he works.  Phil learns that his cousin's failure to complete his antibiotic regimen likely contributed to the evolution of antibiotic-resistant TB in his body.  Phil consults with his friend Stacy, and together they try to understand Dimitri's condition by applying what they are learning in their genetics lab experiment about the role of random mutation in bacterial evolution (including the development of antibiotic resistance) through Luria- Delbrück fluctuation analysis. The same analysis includes calculation of the mutation rate, which Phil realizes is sufficient to cause MRSA and other antibiotic-resistant infections. This case study was originally developed for concurrent use in freshman/sophomore-level genetics, elementary statistics, and precalculus. However, it is also very appropriate for courses in introductory biology, evolutionary biology, and biostatistics. The teaching notes discuss various ways to run the case depending on the mathematics and biology background of students.

Dogs are excellent models for studying genetics, especially disease genetics. Work done in the last 20 years has shown that dogs share many gene-related disorders with people. Each breed is a closed reproductive population with distinct rates of heritable diseases, which dramatically increases the odds of finding disease-related loci. In creating new dog breeds, we reduce the gene pool within those populations, and fix many alleles. This homogeneous background makes it much easier to map QTLs and perform linkage analyses

Say a red gummy bear has a baby with a yellow gummy bear - what percentage of red and yellow do the parents give to their children? Well, assuming gummy bear genetics works the same way we do, they'll have one set of chromosomes from their mum and one from their dad - so 50 percent from each - easy!

The Aedes aegypti mosquito is the major vector for transmission of numerous viral diseases, including yellow fever, dengue, and now, Zika. Interestingly, different subspecies of A. aegypti are known to exist in close proximity but with considerable genetic divergence between them. One major difference between a "forest" form and a "domestic" form is a strong preference in the latter subspecies for human over non-human blood biting. This difference was explored with genetic and neurophysiological approaches by a research group at Rockefeller University and published in a 2014 paper in Nature. This flipped case study uses parts of the Nature paper to focus on elements of the scientific method as well as evolutionary questions raised by the difference in biting preference between the two subspecies. Students prepare for class by watching a video that provides background information about the published study that forms the basis for the case. In class students then work in groups to develop a hypothesis, predictions and proposed experiments to test the idea of different biting preferences.

Although Hardy-Weinberg equilibrium is a fundamental part of introductory biology classes, students often have difficulty understanding its implications. This interrupted case study places students in the role of small teams who are conducting preliminary research into the impact of roads on the population structure of timber rattlesnakes in order to apply for a grant for further research. Research groups consisting of 3-4 students work through a series of questions allowing them to use HWE principles to discover for themselves how deviations from HWE can have implications for conservation biology. Periodic interruptions with help sheets (see Supplemental Materials) allow teachers to maintain an active role in the students' progress, while also demonstrating the collaborative nature of scientific research. Ultimately students formulate formal emails summarizing and interpreting their findings in order to "apply" for the grant. The case is designed for undergraduate students in introductory biology or in lower-level population genetics/conservation courses where connecting basic genetic principles to ecology and sustainability is key.

In this directed case study students follow a nurse practitioner and work with a diagnostics team to determine what is wrong with Tristan, an infant who comes to the clinic with multiple bruises. Students are given background and patient history, and are then given results of various blood tests ordered by the diagnostics team. The exercise emphasizes the physiological process of coagulation and the importance of various clotting factors, especially factor VIII. Students will be introduced to results from several blood tests, including: complete blood count, partial thromboplastin time, prothrombin time, metabolic panel, and factor VIII assay. The patient is ultimately diagnosed with severe hemophilia A and the case then introduces students to this disorder, the genetic determinants, the incidence, and ways to manage the disease. The data in this case are real and the story represents the medical history of an actual patient. Originally developed for pre-nursing students, this activity would also be suitable for majors in physiology or pre-medical students; it could also be used in an introductory genetics or biology course.