Academic journal article The American Biology Teacher

From Phenotype to Genotype: Exploring Middle School Students' Understanding of Genetic Inheritance in a Web-Based Environment

Academic journal article The American Biology Teacher

From Phenotype to Genotype: Exploring Middle School Students' Understanding of Genetic Inheritance in a Web-Based Environment

Article excerpt

Scientists and science education researchers agree that genetics is an extremely important topic in today's society, especially for understanding issues such as genomics and genetic modification (Lewis & Wood-Robinson, 2000; Board on Health Promotion and Disease Prevention, 2005; Venville et al., 2005; Duncan & Reiser, 2007; Tsui & Treagust, 2007). For example, human genomics can help explain the causes of and responses to common chronic diseases that affect the health of a population. Simultaneously, genetics typically involves unseen processes at different organizational levels (e.g., proteins, genes, chromosomes, cells, and organs) and, as a result, genetics has been characterized as abstract. Consequently, many middle school and high school students (as well as college undergraduates) tend to find the topic difficult to learn (e.g., Stewart, 1982; Clough & Wood-Robinson, 1985; Moll & Allen, 1987; Bahar et al., 1999; Lewis & Wood-Robinson, 2000; Tsui & Treagust, 2007). Further, Venville et al. (2005) argued that although extensive research exists on secondary students' understanding of genetics and early primary students' conceptions of inheritance and kinship, research is needed on middle school students' understanding of genetics.

Research shows that students often have considerable nonnormative ideas about this topic even after instruction (e.g., Kargbo et al., 1980; Slack & Stewart, 1990; Banet & Ayuso, 2000; Lewis & Wood-Robinson, 2000). For example, many students believe that the genetic contributions of parents are unequal (e.g., that girls will inherit their mother's traits and boys will inherit their father's traits and that maternal contributions will be greater than paternal ones). These difficulties are likely related to the general problem that students have in understanding the underlying concepts of genes, alleles, and chromosome segregation that are central to understanding the heritability of genetic traits (Venville & Treagust, 1998; Banet & Ayuso, 2000; Lewis & Wood-Robinson, 2000; Wood-Robinson et al., 2000; Lewis & Kattmann, 2004). Other common misunderstandings include (1) difficulties in understanding the concept of the gene (Venville & Treagust, 1998); (2) difficulties in grasping how genotype differs from phenotype (Lewis & Kattmann, 2004); (3) uncertainty about the relationship between genes, alleles, and chromosomes (Lewis & Wood-Robinson, 2000; Wood-Robinson et al., 2000); and (4) difficulties in distinguishing between cell processes such as mitosis and meiosis, including how these processes are linked to the passage of genetic information (Lewis & Wood-Robinson, 2000).

Thus, drawing on the biological education research, Figure 1 depicts a model of how we conceptualize the relationship between genetic inheritance and cell division. This model delineates the connections between key concepts of distinct cell types and cell division, including both mitosis and meiosis, and underlying biological principles that are critical for an integrated understanding of genetic inheritance. The model also shows that genes and chromosomes are contained in all cells, the concept of dominance versus recessive alleles, the production of diploid mitotic products versus haploid meiotic products, and how a zygote results from the combination of cells derived from a female and a male parent during sexual reproduction. The model served as the basis for assessing whether students display an accurate understanding of cell division and genetic inheritance and to pinpoint where key misconceptions arise.

Technology-enhanced instruction has tremendous potential for promoting student learning around complex and abstract science topics such as genetics (Songer, 2006a, b; Tsui & Treagust, 2007; Roseman et al., 2008). For example, the Web-based Inquiry Science Environment (WISE) is a technology-rich learning environment that can scaffold and model inquiry with a navigation system, enable students to interface with real-world problems, and create opportunities for students to monitor and reflect on their learning process (Linn & Slotta, 2000; Kali et al. …

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