Teaching Development Report
An Interactive Multimedia Package to Assist Learning about Genetics and Gene ManipulationMarjory Martin
Faculty of Education, Deakin University
Ruth Leslie, Faculty of Education, Deakin University
Dawn Gleeson, Department of Genetics, The University of Melbourne
Judith Kinnear, Deputy Vice-Chancellor, The University of Sydney
Investigations in Australia, USA and the UK have demonstrated that students find the study of genetics difficult (Smith 1991), perceiving many of the concepts as abstract and the applications as having little or no relevance to their lives. Studies have also shown that teachers find genetics among the most difficult of biological concepts to teach (Mitchell 1992). The limited understanding achieved by students stems from a variety of sources of conceptual difficulty, ambiguous use of terminology, potential confusions in graphic representations, predominant exposure to problem settings that test cause-to-effect reasoning without exposure to problem settings involving effect-to-cause predictions. Similarly, rote application of algorithms has resulted in superficial learning with little deep understanding. Introductory genetics courses generally involve student numbers in excess of one thousand and assistance to individuals makes heavy demand on staff time. Exposure of students to computer-based activities has improved student learning outcomes (Kinnear, Martin and Novak 1982), and the significant changes that have taken place in technology in recent years has opened new opportunities and new ways of providing those activities.
Description of the project
The project developed an interactive multimedia package designed to enhance the teaching of genetics and have a positive impact on student learning. The aim was to introduce beginning biology students to basic structures and terminology related to genetics, and to provide simulations that could act as alternatives to laboratory work and challenge their problem solving skills. The program has three modules: Chromosomes; Genes and Alleles; and DNA - the Genetic Material. Users can access a glossary of terms used in the program via a book icon present throughout the modules.
After a brief introduction to prokaryotic chromosomes, the program concentrates on eukaryotic chromosomes. Aspects dealt with are: composition, structure, how many, and transmission. The Ideas are presented using human chromosomes and karyotypes as exemplars however self tests in this section and others include a range of organisms. Self tests take different forms, from the easy self check of terminology as presented in figure 1, to the more detailed questions relating to pedigrees, blood groups and linked genes.
Figure 1. A straight forward self test that allows users to test their understanding of terms such as homozygous, heterozygous and hemizygous. The feedback on this kind of screen was either Correct or Try again.
A short movie showing mitosis is included in the transmission segment. Meiosis is briefly visited in this section and is revisited at the time linked genes are considered.
Genes and Alleles
Users are introduced to genes by the option of considering one or more genes with some of their alleles in context on each of the human chromosomes. Various relationships between genes and their alleles and the impact of the environment are explored. Genes are considered one at a time and then two at a time, contrasting linked with unlinked genes. This module also contains two simulations - pedigree generation and blood typing.
Users are introduced to pedigree symbols and the pedigree characteristics for the four main modes of inheritance (for example refer to figure 2). Many students made special mention of this feature.
Figure 2. Users can investigate the pedigree patterns of each of the four main modes of inheritance before beginning the pedigree analysis simulation. A frame related to autosomal recessive inheritance is shown. Note that as Two unaffected parents can have an affected child appears, an appropriate segment of the pedigree flashes.
In the program, pedigree generation is based on a statistically driven mathematical model that operates in a way to ensure that each user receives a unique set of pedigrees for analysis. Each time the computer is asked to move to another trait, the choice is made randomly from the four possibilities. A user is in control of how many pedigrees are generated for any one trait before a decision is made about the mode of inheritance. Users can also decide how many unknown traits they investigate. Users may need four or five pedigrees before they have sufficient data to make a confident decision. This activity is far more challenging than a pencil and paper task in which a single pedigree is usually given for a student to analyse. A single pedigree must be fully informative. Computer generated pedigrees are generally less well defined. Figure 3 shows the pedigree analysis screen of the program.
Figure 3. A sample pedigree analysis screen.
The pedigree self test takes the form of sets of multiple choice questions, each relating to a given pedigree. These self tests differ from the type shown in figure 1 in that users receive some feedback if they have chosen an incorrect answer. The feedback is such that the answer is not given however, a comment is made that directs the user to some specific point about the problem. This type of feedback is given in a number of self tests, for example in a problem involving a gene with multiple alleles shown in figure 4.
Figure 4. A multiple choice self test using an example of a gene with multiple alleles. If a user selects incorrectly, the feedback is A mackeral tabby can be TmTm or Tmtb but not tbtb.
In recent years, blood typing has virtually disappeared as an activity in introductory biology courses. Computer simulation provides an opportunity for students to experience the analysis and problem solving that generally accompanied such activities. Blood typing of ABO and Rhesus blood groups is possible in the blood typing simulation. Testing of known samples of blood is followed by unknowns. Note that there is a demonstration of antigen-antibody specificity for users who are unfamiliar with this concept. A sample screen of blood typing is shown in figure 5.
The blood typing segment also contains a comprehensive self test.
Figure 5. A simulation testing known samples is followed by the opportunity to test unknown samples of blood for ABO and Rhesus groups.
DNA - the genetic material
This module includes the structure, replication, changes in and manipulation of DNA. The latter segment comprises plasmids, restriction enzymes, denaturing DNA hybridisation, PCR and gel electrophoresis with activities for some of the manipulations. One type of activity is shown in figure 6.
Figure 6. The manipulation of DNA segment contains activities such as the one shown in this screen.
This genetics package provides an overview of important areas in basic genetics courses. It was developed to introduce students to the learning of some sections of genetics in a more flexible way than is offered with pencil and paper tasks. In the formative evaluation of the program, feedback was obtained from university students who commented most favourably on their enjoyment in using the program. Over 92 per cent of students said they would use further modules of such a program.
The CD-ROM developed is called Genetics and Gene Manipulation and is available for both Mac and IBM computer systems. It is accompanied by a booklet which outlines the contents of the program and includes a number of ten question tests. Each test focuses on either analysis of pedigrees or on blood groups.
The program was developed under a CAUT grant awarded to Marjory Martin, Dawn Gleeson and Judith Kinnear. Ruth Leslie was Research Assistant for the project.
All enquiries about the program should be directed to Professor Marjory Martin, Deakin University.
Kinnear, J.F., Martin, M-D. and Novak, J. (1982). Computer simulation and concept development in students of genetics. Research in Science Education. 12, 89-96.
UniServe Science News Volume 10 July 1998
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