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Show Me My DNA: Engaging Florida Elementary Students in Biotechnology1

Patricia Fajardo-Cavazos and Wayne L. Nicholson2

Figure 1. 
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Recent reports forecast that, if trends continue, United States dominance in science and engineering will slip (Atkinson and Andes, 2009; Shelton and Foland, 2009). Over the past decade, several leading industrialized countries have created national strategies designed specifically to link science, technology, and innovation with economic growth, which has resulted in their increased innovation capacity and competitiveness (Ezell, 2009). Unfortunately, the United States, practically alone among the world's leading economies, conspicuously lacks both a national innovation strategy and an institution to advance one (Ezell, 2009). One fundamental factor recognized by those countries succeeding in technological innovation is the importance of a skilled, world-class workforce (Ezell, 2009). America's share of graduates in science and engineering is declining in comparison to graduates in Europe and developing nations (Freeman, 2006). Many factors underlie this erosion in our scientific preeminence. For example, a recent survey of Florida high school and middle school students found that more than half were not aware of basic concepts in genetics and biotechnology, but greater than half of students surveyed expressed a desire to learn more (Drew et al., 2006). This study found that interest in learning about genetics and biotechnology declined between the middle school and high school years, indicating that the window of opportunity for sparking students' interest in science begins to close at an early age (Drew et al., 2006). A crucial key to the reversal of this disturbing trend relies on the early engagement of elementary schoolchildren in the wonder of science.

When asked to name the single moment when they were hooked by science, many modern molecular biologists immediately describe the first time they isolated the genetic material, DNA, from cells. They often describe their awe at witnessing the long ropy strings of DNA precipitating in a test-tube. This single lab moment seems to be the first time students realize that the blueprint of life is not just an abstract double-helical squiggle on the blackboard, but a real chemical compound which they can manipulate with their own hands and minds. This eye-opening moment can be a springboard to further exploration of the biological world.

Isolation of DNA has been incorporated in pre-college educational science programs for a long time, and a number of kits providing the materials to conduct this exercise in the classroom are commercially available. However, middle to high school students are typically the target group for this activity. Bringing a DNA isolation laboratory exercise to elementary school classrooms requires special considerations, such as safety, difficulty, cost, duration, and the age of the particular group of students.

The following classroom laboratory exercise was designed to be completed within one hour by an average-sized elementary school classroom (20-25 students). It was developed as part of a hands-on Career Day presentation at Robert Louis Stevenson Elementary School, a Brevard County public school. The attending students and their teacher first listened to a brief introduction consisting of:

  • an explanation of the DNA molecule as the blueprint for life;

  • an explanation of genetic engineering and its benefits; and

  • a flow chart of the DNA extraction procedure.

The students then proceeded to extract DNA from their own cheek (buccal) cells. The point was made that the procedure is basically the same technique used by scientists to extract DNA for:

1. Genetic engineering,

2. Detection of genetic diseases, and

3. Forensic analysis.

Materials and Methods

All procedures to extract DNA from cells share key steps that include the following:

  1. lysing, or breaking open, the cells with detergent to release the cell contents;

  2. separating proteins and other cellular components from the DNA with enzymes that digest proteins; and

  3. precipitating the DNA strands out of solution with salt and alcohol.

Each student was provided with the following materials:

  • One disposable 3-oz paper/plastic cup containing 7 milliliters (ml) of Gatorade® (must be clear with no colored dye)

  • One 15-ml conical-bottom screw-cap disposable polypropylene centrifuge tube with graduations [Fisher Scientific S50712]. The 5 ml line was made more apparent with a black marker

Materials the instructor needs:

  • 2 micropipettors with disposable tips, one capable of measuring 10 microliters (µl) and the other 250 µl.

  • 2 disposable 10-ml pipets

  • Pipet bulb for 10-ml pipet

  • Water Bath with thermometer, set at 55°C (130°F)

  • Test tube rack in the water bath

  • Permanent markers

  • 10% SDS (detergent) solution (prepare the solution for the class by dissolving 10 g sodium dodecyl sulfate in a final concentration of 100 ml water)

  • 5 Molar (M) NaCl salt solution (prepare the solution for the class by dissolving 29 g NaCl in a final concentration of 100 ml water)

  • Protease K (optional)

  • Isopropanol (must be pure; 70% rubbing alcohol does not work)

Note: Hot tap water in a container could be used instead of a water bath. Before using this alternative, verify that the water supply temperature is 55°C (130°F).

Procedure

  1. Each student collects his/her cheek cells by swishing the Gatorade® in his/her mouth and spitting back into the cup. For best yield, vigorous swishing accompanied with gentle “scraping” of the interior cheeks with the molars (no blood!) was encouraged. Repeat swishing of the same sample 2-3 times.

  2. Student writes his/her name on the conical centrifuge tube provided. Pour the obtained sample into the tube up to the marked 5-ml line. Discard the rest.

  3. To each student's tube, the instructor adds:

µl of 10% SDS

ml of 5M NaCl

µl of Protease K (optional)

  1. The student caps the tube, and mixes the contents by gently inverting the tube several times.

  2. All tubes are placed in a water bath at 55°C for 15 min.

  3. The instructor slowly layers 4 ml of isopropanol into each tube and caps the tubes tightly.

  4. After a 5 min wait, each student inverts his/her tube several times and observes the white material, their DNA, appear.

Results

Students showed a remarkable degree of excitement. Just as importantly, their teacher participated and expressed that she had learned from the exercise. Many questions were asked, often revealing several common misconceptions about DNA and biotechnology. These served as excellent springboards for discussion. The visible reactions of children, as well as their subsequent thank-you notes, indicated that seeing their own DNA, and taking the tube containing it back home, made the biggest and most lasting impressions.

Conclusions

Recently, reports of DNA workshops for elementary school students have become more common. However, most of these laboratory exercises (i) are directed at older students (Drake, 2009), (ii) extract DNA from plant materials (Drake, 2009; NCSU, 2008), or (iii) are done in a dedicated facility, limiting accessibility (Slager, 2009). The above exercise demonstrates that the extraction of DNA in an elementary school classroom is a feasible and enjoyable introduction to genetics and biotechnology principles. The laboratory experience we present, simple to execute and in which younger students visualize their own DNA, has a great chance of reaching the most minds.The experiment offers elementary school teachers and students the chance to see that biotechnology is approachable by anyone. It is our hope that this experience generates excitement and curiosity about biotechnology, encouraging students to learn more about this field that is increasingly affecting our lives, or even to consider entering a scientific career.

To do this activity in a classroom or other adult-supervised setting, the materials can be obtained from Fisher Scientific (http://www.fishersci.com/) or Sigma-Aldrich Chemicals (http://www.sigmaaldrich.com). As the supplies are commonly used in laboratories, local high schools, community colleges, or university science departments are excellent resources and likely to have access to the materials. Additionally, kits for DNA isolation can be ordered for a fee from BioRad (www.bio-rad.com) and Edvotek (www.edvotek.com).

References

Robert D. Atkinson and Scott M. Andes. The Atlantic Century: Benchmarking EU and U.S. Innovation and Competitiveness. The Information Technology and Innovation Foundation. February 25, 2009 http://archive.itif.org/index.php?id=226

Ezell, S. 2009. America and the world: we’re #40! Democracy: A Journal of Ideas Issue#14, Fall 2009. http://www.democracyjournal.org/

The Race for World Leadership of Science and Technology: Status and Forecasts. Presented at the International Conference of Scientometrics and Informetrics in Rio de Janeiro in July, 2009 by R.D. Shelton and P. Foland.

Richard B. Freeman. 2006. Does Globalization of the Scientific/Engineering Workforce Threaten U.S. Economic Leadership? National Bureau of Economic Research Working Paper No. 11457 Issued in July 2005. http://www.nber.org/~freeman

Jennifer C. Drew, Joy C. Jordan, and Eric W. Triplett. 2006. Building a Genetics Curriculum: Needs Assessment Survey of Middle and High School Students [Online]. EDIS Florida Cooperative Extension Service, University of Florida, Gainesville. Retrieved August 20, 2006 from http://edis.ifas.ufl.edu/MB002

Footnotes

1.

This document is MB003, one of a series of the Microbiology and Cell Science Department, UF/IFAS Extension. Original publication date October 2006. Revised November 2009. Reviewed July 2013. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Patricia Fajardo-Cavazos, Ph.D., assistant scientist, and Wayne L. Nicholson, Ph.D., associate professor, Microbiology and Cell Science Department, Institute of Food and Agricultural Sciences, University of Florida, Kennedy Space Center, 32899

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.

All chemicals should be used in accordance with directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.