iTAG Barley: A 9-12 classroom module to explore gene expression and segregation using Oregon Wolfe Barley

Authors: MAFFIN, LANCE - Bondurant-Farrar High School; HALL, GARRETT - South East Polk High School; HUBBARD, TAYLOR - Ankeny High School; WHIGHAM, EHREN - Iowa State University; Wise, Roger

Submitted to: American Society of Plant Biologists
Publication Type: Book / Chapter
Publication Acceptance Date: 5/2/2012
Publication Date: 5/23/2012
Citation: Maffin, L., Hall, G., Hubbard, T., Whigham, E., Wise, R.P. 2012. iTAG Barley: A 9-12 classroom module to explore gene expression and segregation using Oregon Wolfe Barley. American Society of Plant Biologists. http://c.ymcdn.com/sites/my.aspb.org/resource/group/a9372bf4-9ae4-4d0b-ad0c-595c9dfc3543/itag_v20_march_2013.pdf.

Interpretive Summary: One of the basic concepts in biology is that an organism’s physical traits are controlled by its DNA. In other words, one’s genotype for a particular trait controls the phenotype that is expressed. Yet, this connection between DNA and physical characteristic is not always made by students. The Gene Expression and Segregation Analysis (GESA) Project is a module of laboratory and classroom activities designed to help students make this connection. The laboratory portion begins with students planting and growing barley plants so that phenotypic variation can be observed first hand. One trait in particular, the difference between “awned” and “hooded” plants, is the focus of the basic Learning Module. The barley plants in the photos exhibit these two phenotypes. The Learning Module also includes protocols for DNA Extraction, Polymerase Chain Reaction, and Gel Electrophoresis. Students get the opportunity to experience these basic biotechnology techniques, and the final results of the electrophoresis allow students to see the DNA polymorphisms among plants with different phenotypes. In addition, several extension activities are provided in the Extension Module. These protocols can be used in addition to the Learning Module, or separately in whatever way that helps teachers to meet their curriculum. Some of the activities may be useful if you are working with younger or more inexperienced students, while others move beyond the Learning Module and work best with more advanced students. This outreach program integrates basic genetics with agriculture and human health using the easy-to-grow plant model, barley. These themes are the foundation for more complex genomic technologies, such as those used to solve human and agricultural disease, thus, providing young researchers with the tools to advance science in the 21st century.

Technical Abstract: The Oregon Wolfe Barleys (OWBs) are a model resource for genetics research and instruction (http://barleyworld.org/oregonwolfe ; http://wheat.pw.usda.gov/ggpages/OWB_gallery/ISS-OWB/index.htm). The population of 94 doubled haploid lines was developed from an F1 of a cross between dominant and recessive marker stocks advanced by Dr. Robert Wolfe. Segregating plants from the OWB doubled haploid (DH) population are easily grown on a lighted window bench in the classroom. These lines originate from a wide cross and have exceptionally diverse and dramatic phenotypes, making the population attractive for teaching basic plant development, genetics, and genomics in high school biology. Students can observe the spikes for seed-coat color, two row vs. six row (encoded by Vrs, a domestication trait), hooded vs. non-hooded (Kap: encoded by BKn3 of the Knox gene family - a homoeotic mutation where the awn is replaced by another floret), and long awn vs. short awn traits (encoded by Lks2). In addition, plants homozygous for the recessive allele at lks2, the expression of the hooded phenotype is masked, resulting in the expression of a short-awned, rather than hooded, phenotype. Thus, students gain experience in phenotype observation and firsthand knowledge of genetic history related to cellular pathways, grain domestication, and developmental mutations in plants. Students perform the polymerase chain reaction (PCR) to amplify the Kap and Vrs1 (HvHox1) genes using DNAs they isolate from the segregating plants, size fractionate the products on agarose gels, and document their results. Interactive exercises are presented on co-segregation of PCR products and whole plant phenotypes in the OWB population. This module grew out of conversations between high school science teachers and USDA-ARS researchers at Iowa State University. During the summer NSF-sponsored, Research Experience for Teachers program (RET), discussions on how to incorporate research into the classroom were common. Everyone agreed that high school students were capable of understanding and conducting PCR; the challenges were how to fund and implement the concept. We decided on the OWB population barley because it is easy to grow, the plants are phenotypically diverse and easy to score, and the DNA extraction is straightforward. This module was included as a “broader impacts” component of NSF Grant #0922746. As of spring 2012, this module has been used successfully in 25 Iowa high school biology classrooms, impacting >600 students.