The course breakdown process

To effectively unpack the syllabus, I decided to first put together a summary of what I had come to understand as the core knowledge of genetics from the review of the literature on the teaching and learning of genetics that I had done and then use the summary as a guide in unpacking the syllabus. The summary that I produced is presented below.

The core knowledge of genetics

From a review of literature on the teaching and learning of genetics (e.g.Lewis & Kattmann, 2004; Lewis et al., 2000a; Stewart, Cartier, & Passmore, 2005) the core knowledge of genetics includes:

1. The knowledge of genetic information molecules (DNA, nucleotides, genes, RNA) 2. The mechanisms that link genes to traits (transcription, translation).

3. The knowledge of meiosis i.e. the ability to transmit genetic information to future generations

4. The knowledge of classical or transmission genetics which looks at patterns of inheritance that are observed when organisms reproduce sexually

Duncan, Rogat, and Yarden (2009) described this core knowledge in terms of models. They termed the knowledge of genetic information molecules (DNA, nucleotides, genes, RNA) the

molecular model, the knowledge of meiosis as the meiotic model and the knowledge of

transmission genetics as the inheritance model. They argued that for one to reason adequately about and to account for genetic phenomena one needs to understand all the three models. Their description however, left out the mechanism that links genes to traits which I have decided to call the gene expression model. I am calling this mechanism the gene expression model because it is the information that is carried by the genes that is responsible for the formation of proteins and the proteins that are formed in turn lead to the development of the traits that we observe in organism. Although there is nothing in the literature about the need for an adequate knowledge of the cell and of mitosis for one to understand genetics, I thought that students would need this knowledge if they are to

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adequately understand genetics. This is because most10 living organisms are composed of cells and it is inside the cell that genetic information is located. In addition, the events of meiosis and protein synthesis occur inside the cell. It is important to know about mitosis because in multicellular organisms, genetic information is passed on from cell to cell through the process of mitosis. I have called the knowledge about the cell and about mitosis the

cellular model and the mitotic model respectively. For me then, the core knowledge of

genetics, includes the following: the molecular model, the gene expression model, the meiotic model, the inheritance model, the cellular model and the mitotic model. After putting together into a summary, the core knowledge of genetics that students need to know, I then used this summary to rework on my course outline.

Determining the content to include in the course outline and validation of that

content

In order to come up with the topics for my genetics course, I first listed what I considered to be the main concepts in genetics based on the summary above. I also considered the genetics content in the documents that I had read namely: The CAPS document, the IEB syllabus, the ‘O’ and ‘A’ Level Cambridge syllabi and the US Atlas of Science Literacy. After listing the main genetics concepts, I constructed a concept map to reflect my understanding of the genetics that I would need for teaching (See Figure 13 below). I then gave copies of the concept map to three high school Life Sciences teachers and to four Life Sciences lecturers in our Science Division for their comments and input. Giving the concept map to Life Sciences lecturers and high school teachers was a necessary step as their comments would be useful in drawing my attention to possible gaps in my content knowledge and/or inconsistencies. I gave them the map whose final form became that shown in Figure 14 with the following guidelines: The concept map represents my understanding of genetics

concepts for teaching and the relationships between them. Please comment on the following:

 The concepts chosen

 The links that explain the connections or relationships between the concepts  The information that the whole map conveys

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Two of the three high school teachers were happy with the map as it was. The third high school teacher was of the idea that the map should also show links to applications of genetics like biotechnology concepts (cloning, genetic engineering, DNA finger printing). These biology topics are found in the CAPS document. I had however, deliberately left out the biotechnology concepts because in our Life Sciences programme, biotechnology is done as a standalone course. The four Life Sciences colleagues that I asked to comment on the map were also happy with the genetics content that I had presented in the map. One colleague added that I should include a link between unit of inheritance and genetic code which was missing. The link was added. Another colleague was of the idea that the concept of gene should be presented as a model as I had done with other concepts like meiosis. This is because her experience of teaching about genes has shown her that students treat a gene as a physical entity that can be seen and be isolated. While I could represent a gene as a model, this suggestion was not added to the map as in the map genes fall under the molecular model. Secondly, a gene is a single concept whilst other models in the core knowledge of genetics all included a number of concepts and/or processes. Furthermore, with advances in biotechnology, single genes can now be cut and separated from DNA in some organisms using restriction enzymes. The third colleague was of the idea that the concepts of codominance, incomplete dominance and multiple alleles were monohybrid crosses and hence must be put under monohybrid inheritance. This was done. Figure 14 shows the final map. The yellow blocks show content that is covered in the course that precedes the genetics course. The blue block shows content that is covered in the previous course but which I also revise in some detail in my course. The grey blocks show the content that I teach. The white blocks show content that was not being covered anywhere in the Life Sciences programme at the time of doing my course breakdown.

After the concept map exercise, I revisited my list of topics in the original course outline and made a number of changes. The course outline with changes is shown in Figure 15 below.

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Week 1: An exploration of students’ prior knowledge of genetics. Basic structures of genetics (nucleotides, DNA, genes and chromosomes)

Week 2: Meiosis

Week 3: Mutations, genetic disorders, genetic testing and counseling

Week 4: Mendel, monohybrid inheritance, genetic diagrams, Punnett squares

Week 5: Co-dominance, Incomplete dominance and Multiple alleles

Week 6: Sex determination and sex-linkage

Week 7: Dihybrid inheritance?

Figure 15: The proposed list of genetics topics for the new genetics course outline