9: Using Genetic Crosses to Analyze a Stickleback Trait

Learning objectives

• Characterize stickleback fish according to the presence or absence of pelvic spines.
• Use Punnett squares to predict the frequencies of genotypes and phenotypes in the offspring of a genetic cross, based on the genotypes of the parents.
• Develop hypotheses about whether a phenotype is dominant or recessive.
• Evaluate the evidence in support of or against the hypothesis