Module 6 Lesson 2 - 5 (Lab)

Many traits have two clear phenotypes, such as tall or short pea plants. Sometimes these traits are controlled by a single gene with two different alleles. If there is complete dominance, one allele is dominant and the other recessive. When an organism has two copies of the dominant allele, or one dominant allele and one recessive allele, the dominant trait is expressed, such as green pea colour. Only when the organism has two copies of the recessive allele does the recessive phenotype come through, such as yellow pea colour.

In this simulation, you will explore Drosophila wing length colour as a single gene trait.  You will cross pure breeding parents to produce an F1 generation, and then cross flies from the F1 generation to produce the F2 generation.  By the end of this activity you should have a good understanding of how dominant and recessive alleles perform and how to determine the expected genotypic and phenotypic ratios for a monohybrid cross involving complete dominance.