From DNA to Organism: A Study in DNA Function for the High School Biology Classroom
 
 

Introduction

     Why Create this Learning Program?

         The “typical” high school science class consists of a large number of “cookbook” labs where the focus is on following the steps provided and collection of data. The majority of the lab is focused on filling in a certain number of “blanks” in order to complete the exercise. Not enough emphasis is put on the collection and interpretation of data. Application of science typically focuses on developing and testing a hypothesis, solving problems as part of this process, and using techniques to collect and interpret the meaning and significance of data. The protocols used are a tool to obtain the data and should not be the focus of the lab. The focus should be on the problem at hand (hypothesis testing), what the data means in terms of that problem and the conclusions that can be drawn from that data. This learning program is designed to help students gain more experience with how science really works. As part of this experiential learning process (i.e. hypothesis testing), students will be exposed to many powerful tools currently used to manipulate, clone, and analyze DNA.

         The lab modules cover an area of biology that is taught in most classrooms as reading -intensive subject matter supplemented by a number of “dry labs.” Many high school level biology teachers lack the equipment, knowledge base and comfort level to carry out the lab activities that would go along with the study of DNA structure/function and current technology used to manipulate DNA. Despite its prevalence in the news and popular media (e.g. television shows such as CSI, etc.), most students do not experience these technologies during their high school careers (many not in their college careers) except for the occasional lab run using a kit purchased from a scientific supply company. The teacher who developed this program did not use PCR, electrophoresis, or DNA cloning until graduate school, despite obtaining a B.S. degree is in biology! The learning program offers students of introductory biology courses at the high school level (although it could be used at the introductory college level as well) a chance to see and use some of the technologies being used in current cutting edge research today in the framework of a series of interconnected learning modules attempting to solve a central question. The hope of the authors of the program is that the students who take part will leave having a better understanding of what DNA is, and how it really functions in the organisms that it codes for. They will then be able to use their knowledge to make better, more informed decisions on the biotechnology issues facing today’s society, GMO foods, cloning, etc.

         Lastly, the learning program was designed around the plant Arabidopsis thaliana, a common subject in many genetics research labs, both plant and animal. The rationale supporting the program’s focus on this model plant may be surprising to those involved in teaching biology.  In addition to testing hypotheses and learning how to collect and interpret experimental results as part of this process, this learning program seeks to acquaint students with the concept of a “ molecular genetic superhighway of information flow .” The lab modules connect the information contained in the nucleotide sequence of a gene or the genetic code to the transcribed nucleotide message and the amino acid sequence of the protein into which it is translated.  Continuing on the pathway of molecular genetic information flow, the function of a protein is related to its amino acid sequence. The function of the protein at a cellular level is related to how the protein’s function affects an entire organism.  This integration, from gene to organism, uses easily obtained gene sequences as well as intact organisms that contain mutations in the gene encoding the particular protein.  The integration of these concepts into experiential laboratory exercises can most easily be undertaken in the high school classroom using the model plant Arabidopsis thaliana. Over the last decade or so, the National Science Foundation has supported the development of an infrastructure of ” tools” making use of this plant. Seeds of plants that contain mutations in specific genes, cloned nucleotide sequences encoding thousands of its proteins, as well as its entire genome sequence have all been developed and made available to virtually any high school teacher at little to no cost. Teachers who wish to incorporate this program into their classroom can therefore take advantage of these tools and infrastructure developed to aid in teaching as well as supporting cutting-edge research.

         A final comment should be made on the field of botany. Botany, once a staple of an introductory biology course, has been pushed out of curricula in favor of more “current” topics like DNA and genetics. Many students make it through their high school career without really looking at plants and how they work. The exception to this is the units covering photosynthesis. With the focus on animals, many students probably leave high school with the mistaken idea that animals have DNA but plants do not! This module, by using a plant as its central character, integrates a bit of botany and plant science into the studies of DNA and biotechnology. It is important for the students of today to understand the role that plants play in the technology of tomorrow.

    How is the Program Setup?

         The focus of the learning program is to make it as easy as possible for a teacher to use it in their classroom. Everything from what materials to set up, and where to get them, to timeframe of individual parts of the modules has been laid out for the participating teacher. The hope is that any teacher, from someone with a background in molecular biology to someone fresh out of school with very little biology background, can run the program from start to finish with confidence that it will work.

         The learning program follows the science from an organism’s phenotype to DNA and back again using Arabidopsis thaliana as a model organism. The program is broken into six different modules that have been designed to be used either as a part of the larger learning program or as stand alone activities that can be run as a part of a currently used curriculum. For example, if you choose to run module 1, where the students observe different mutant plant phenotypes, you could incorporate that into your discussions of Mendelian genetics, DNA structure/function, or evolution. Likewise, you could pick and choose any of the other middle modules to run individually as well. The flexibility for the teacher to run the whole program, as it was designed to be run, or modules from it should help teachers to better use the materials in their classroom.
           
         Each module is based on the correspondence from a Dr. Berkowitz, a researcher from a local university, asking for the students help in finding answers to problems that he has run into during his research. The letter format of the modules creates a more student-centered learning experience. Rather than just being given the lab and steps to follow, they are presented with a problem and given suggestions on how to solve it. They are also given biological research tools in the form of protocols that will allow them to manipulate the plants and the DNA to gather data to solve the problem at hand. The hope is that by introducing the problem and then giving the students different tools to solve it, they will better learn the concepts that are being taught.
           
         The other advantage of the letter format is that the teacher is given the freedom to ask students for different levels of work for the different parts of the learning program. For example, in Module 1, where students observe and describe mutant plant phenotypes, the teacher could ask the students to write up their data and observations to be passed in. This makes the focus of the lab data collection skills and can lead into discussions of good and bad data. For the same module, the teacher could ask for a formal lab write up with the problem, procedure, data and conclusions. You could even ask students to become real scientists by writing up their findings for the whole program into a journal format like they were submitting their findings to a peer-reviewed journal. The key again is flexibility for the teacher.

    Tips for Teaching with your Biology Textbook

         Most teachers are used to teaching with a text to accompany the classroom material. This learning program does not include references to any text. I have had luck using a standard biology text book as a reading supplement for this program. I give the students readings that go along with the material covered in the modules and assign questions from the reading as homework. This seems to effectively add to the students’ understanding of the material.

 
Contact info:

Dr. Gerald Berkowitz
Agricultural Biotechnology Laboratory, U-4163
Room 302C
1390 Storrs Rd.
University of Connecticut
Storr, CT 06269-4163
E-mail: gerald.berkowitz@
uconn.edu

phone: 860-486-1945