Using Genetic Crosses to Analyze a Stickleback Trait

Topic

Resource Type

Level

High School — General High School — AP/IB

Saved By

33 Users

Description

In this hands-on activity, students analyze the results of genetic crosses between stickleback fish with different traits. It complements the film Evolving Switches, Evolving Bodies.

The activity begins with watching a portion of the short film Evolving Switches, Evolving Bodies. Students then apply the principles of Mendelian genetics to analyze the results of genetic crosses between stickleback fish with different traits. Students use photos of actual research specimens (the F1 and F2 cards) to obtain their data; they will then analyze the data they collected along with additional data from the scientific literature. In the extension activity, students use chi-square analysis to determine the significance of their results.

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Student Learning Targets

Use Punnett squares to predict the frequencies of genotypes and phenotypes in the offspring of a genetic cross, based on the genotypes of the parent.
Develop hypotheses about whether a phenotype is dominant or recessive and evaluate the evidence in support of or against these hypotheses.
Simulate a cross to determine the genotype of an individual with a dominant phenotype.
Use chi-square analysis to determine the significance of genetic data.

Estimated Time

One to two 50-minute class periods.

Key Terms

F1 generation, F2 generation, genotype, offspring, phenotype, Punnett square, test cross, trait, statistical analysis

Primary Literature

Cresko, William A., Angel Amores, Catherine Wilson, Joy Murphy, Mark Currey, Patrick Phillips, Michael A. Bell, Charles B. Kimmel, and John H. Postlethwait. “Parallel genetic basis for repeated evolution of armor loss in Alaskan threespine stickleback populations.” Proceedings of the National Academy of Sciences 101, 16 (2004): 6050–6055. https://doi.org/10.1073/pnas.0308479101.