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These case studies heralded a new appreciation for the phenomenon of genetic chimerism-when an individual carries two or more genetically distinct cell lines in different parts of her body. Until the advent of techniques for blood typing and karyotyping cells, genetic chimeras where thought to be very rare. They only came to light when the phenotypes associated with the two distinct genomes were so discordant that the resulting individual was clearly exceptional, with patches of distinct skin coloration throughout the body, for example, or hermaphroditic genitals. In reality, genetic chimeras may be quite common, disguised in perfectly normal bodies harboring genetically distinct cell lineages.

This lesson, using segments from the PBS series Faces of America, explores the various types of genetic information contained in the human genome. The Introductory Activity examines the structure and composition of chromosomes and DNA, and can be used as a review or introduction to the topic. Following that, students will participate in a hands-on activity reviewing basic Mendelian genetics and the difference between genotype and phenotype. Students will also learn about different ways of tracing ancestry through DNA, and apply that to patterns of human migration and genetic population sets known as haplogroups. In the Culminating Activity, students will develop methods for determining the genetic heritage of their class, school, or community.

There are a significant number of genetics curriculum resources designed by different companies, curriculum development outlets, state curriculum designers and individual teachers. What resources are good? How do you know? As part of the Geneticist-Educator Network of Alliances (GENA) Project, a Curriculum Content Review Committee was formed to review readily available classroom resources about patterns of inheritance. Click here to see original evaluation form used by the committee and here to see the summary of the committee's review.

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.

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.

webquest with student group members assuming different roles when investiigating genetic disease 

Genetic tests are now available to look for specific heritable diseases like Huntington's, assess your risk of developing conditions like heart disease, and more. Learn about four different types of genetic testing and take our poll. Would you take these tests yourself?

This video excerpt from NOVA uncovers the genetic mystery that nearly killed Alexis, now 14, and introduces the debate surrounding genetic testing at birth. After diagnosing Alexis and her twin brother Noah with cerebral palsy at a young age, doctors later discovered that the twins shared a rare genetic mutation that led to a condition that mimics cerebral palsy. The twins improved after receiving treatment, but then Alexis took a turn for the worse. Thanks to whole genome sequencing, doctors discovered a second problem linked to the mutation and gave her a different treatment that saved her life.

One concern repeatedly raised by critics who don't want the FDA to give the transgenic fish the green light: What would happen if these fish got out of the land-based facilities where they're grown and escaped into the wild? Would genetically modified salmon push out their wild counterparts or permanently alter habitat? In a review paper published this month in the journal BioScience, scientists tackle that very question. Robert H. Devlin, a scientist at Fisheries and Oceans Canada, led a team that reviewed more than 80 studies analyzing growth, behavior and other trait differences between genetically modified and unaltered fish. The scientists used this to predict what might happen if fish with modified traits were unleashed in nature.

Over the past few decades, genetic research has revealed two deep truths about people. The first is that all humans are closely related-more closely related than all chimps, even though there are many more humans around today. Everyone has the same collection of genes, but with the exception of identical twins, everyone has slightly different versions of some of them. Studies of this genetic diversity have allowed scientists to reconstruct a kind of family tree of human populations. That has revealed the second deep truth: In a very real sense, all people alive today are Africans.

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.

Genetic differences among ethnically diverse individuals are largely due to structural elements called copy number variants (CNVs), according to a study published today (August 6) in Science. Compared with other genomic features, such as single nucleotide variants (SNVs), CNVs have not previously been studied in as much detail because they are more difficult to sequence. Covering 125 distinct human populations around the world, geneticist Evan Eichler at the University of Washington in Seattle and an international team of colleagues studied the genomes of 236 people-analyzing both SNVs and CNVs. "The take-home message is that we continue to find a lot more genetic variation between humans than we appreciated previously," Eichler told The Scientist.

This initial module from the GENIQUEST project introduces the dragons and the inheritance of their traits, then delves into meiosis and its relationship to inherited traits. Students examine the effects of choosing different gametes on dragon offspring, and learn about genetic recombination by creating recombination events to generate specific offspring from two given parent dragons. Students learn about inbred strains and breed an inbred strain of dragons themselves. Lastly, students investigate a mysterious new dragon trait and use the properties of linkage and inheritance to examine the trait's relationship to other, known dragon traits.

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.

An innovative new breeding simulation helps reveal genetic ratios in offspring. With the heredity level of the ConnectedBio Multi-Level Simulation (MLS), students breed pairs of mice with different fur colors and observe the phenotypic ratios in the resulting offspring. The goal of this activity is to demystify the science behind Punnett Squares and encourage students to explore data and statistical representations in genetics and heredity.

An international team led by Professor Itai YanaAi of the Technion-Israel Institute of Technology Department of Biology made the discovery after using an extraordinarily powerful technique known as CEL-Seq. CEL-Seq monitors individual cells for their gene activity (as detected via mRNA)-and they applied it across 10 different species, with CEL-Seq being applied to 70 embryos per species. In particular, they were interested in whether the animal classification of phylum-which separates animals into groups according to their body plans-is actually a useful tool for placing animals into groups, as well as what genetic attributes are the same and different between the different phyla.

Students begin by watching the online video clip and completing a worksheet. After that assignment, instructors can decide which of the two activities (or both!) to use in class. In Activity 1, students identify the locations on chromosomes of genes involved in cancer, using a set of 139 "Cancer Gene Cards" and associated posters. In Activity 2, students explore the genetic basis of cancer by examining cards that list genetic mutations found in the DNA of actual cancer patients. Small-group work spurs discussion about the genes that are mutated in different types of cancers and the cellular processes that the affected genes control. The Activity 1 and 2 Overview document provides short summaries of the two activities along with key concepts and learning objectives, background information, references and rubrics, and answers to students' questions. Both cancer discovery activities are appropriate for first-year high school biology (honors or regular), AP and IB Biology. Activity 2 is also appropriate for an undergraduate freshman biology class.

This case study focuses on the relationship between evolution and plasticity using a hands-on, inquiry-based approach. Students view examples from the literature that illustrate the difference between nature and nurture, or the relative contributions of genes and the environment in shaping phenotypes. Using the Trinidadian guppy system as an example, students learn about seminal work in the field in addition to exploring quantitative genetic techniques used to partition phenotypic variance between genes (G) and the environment (E). They use real data from one of the publications cited in the case to graph reaction norms illustrating GxE interactions at the family and population level. The inquiry-based approach means that students are introduced to new concepts in a stepwise fashion, and asked to develop and build their understanding using causal, explanatory evidence. The case concludes with an exercise in which students apply their knowledge to a real conservation problem in Trinidad and Tobago, where guppies are native. This case would be appropriate for an upper level biology, genetics, or evolution course.

In this clicker case study for a flipped classroom, students familiar with the stages of meiosis work in small groups to determine the predicted genetic makeup of the parthenogenetic offspring of a Komodo dragon, based on four different types of parthenogenesis. Students then learn about the actual genetic makeup of the offspring and determine how meiosis was modified to allow parthenogenesis in this fascinating lizard. The sex of the offspring is explained, based on ZW/ZZ sex determination. A video specifically made for this case prepares students for the in-class activities, which are guided by a PowerPoint presentation. The case also examines how facultative parthogenesis may be adaptive in Komodo dragons and the implications of facultative parthogenesis to conservation of these vulnerable lizards. The case was developed for a general biology class, but could also be used in an introductory course on conservation or cell biology.

"This case study introduces students to Duchenne muscular dystrophy (DMD) and its underlying genetics, cell biology, and some of the associated biochemical pathways.  DMD is an X-linked disorder characterized by progressive muscle weakness and wasting due to the absence of a protein called dystrophin, which in turn causes degeneration of skeletal and cardiac muscle. There is currently no established cure for this disease.  The case follows the progress of "Casey," an undergraduate student who has just declared her biology major and is interested in expanding her scientific understanding of the different fields of biology. The case is organized in three parts: genetics, cell biology, and biochemistry, each exploring DMD through its unique lens. Throughout the case, Casey is presented with multiple outlets of information, including class lectures, direct e-mail interaction with a professor, scientific journals and websites, from which she (and any student engaged with the case) gathers knowledge about DMD."