Lab Summary This multi-week guided inquiry begins by prompting students to consider the difference between human traits controlled by a single gene and those that are dictated by the interaction of multiple genes.  The question that students are then confronted with is: How is eye color determined in fruit flies (Drosophila melanogaster).  This question is addressed by breaking it into three related questions: How do mutations affect the biochemical pathway that leads to eye pigment production? What are the inheritance patterns for the gene(s) involved in determining eye color? If multiple genes are involved, do they interact to produce the different eye color phenotypes? Over the next several weeks students establish their own fly cultures (wild type, sepia & white eye), conduct experimental F1 and F2 crosses, harvest and separate eye pigments using paper chromatography to test their hypotheses stemming from the questions above.  Inferential statistical analysis of the experimental cross data is used to draw conclusions regarding the student's initial hypotheses.

• discuss the relationship between genes and their protein products.
• explain why the genes explored in this investigation are epistatic.
• discuss why a mutation in a given gene results in a given eye color phenotype given the biochemical and genetic control of eye color.
• given an enzyme-catalyzed biochemical pathway; predict how various mutations in the genes for these enzymes would influence the results of paper chromatography of pathway products.
• use data from genetic cross experiments to test predictions about how mutations in epistatic genes  influence expression of enzymes and consequent phenotypic effects.
• use data from genetic cross experiments to test predictions about the inheritance pattern for a gene mutation.

• generating predicted results from genetic cross experiments which test hypotheses related to gene expression and inheritance patterns.
• testing genetic cross predictions above using inferential statistical analysis (Chi Square test).
• generating the null and alternative hypotheses.
• conducting a Chi Square analysis by hand and using the Chi Square function in MS Excel.
• discussing the results of the chi square test with regard to decisions regarding the null & alternative hypotheses.
• evaluating what their decision regarding the null and alternative hypotheses mean in the context of the experimental genetic hypotheses being tested.

Learning Theory & Pedagogy

The more traditional highly guided science lab model typically uses scientific methods but these kinds of labs usually prompt students to follow (often mindlessly) a set of science instructions, which guide students through a process of finding out about something, for which “an answer” or outcome is preplanned and already known.  This is more akin to following a cookbook recipe, and like a recipe, is often thought to have failed if the expected results don’t materialize.  This more “cookbook” approach to science labs does little to help students develop literate conceptions of the nature of scientific knowledge (validity, tentativeness, limitations, importance of experimental design features etc…).  So instead the focus of this practicing inquiry lab is instead to build on students' scientific inquiry skills, by guiding them through some aspects of the experiment (questions, protocol) but leaving many of the decisions (hypothesis formation, predictions, statistical methodology) up to the students.   Students are likely to be more invested in a science experiment if they are allowed to make critical decisions about the design and execution.  This elicits some ownership of the experiment to the students, generating intrinsic interest in the outcome, while also giving them practice applying important biological concepts and practicing designing and interpreting experiments.

• An instructor guide which provide lab instructors with lab preparation instructions, suggested materials, learning theory and pedagogical suggestions.