A. H. Sturtevant, a student of T. H. Morgan, published a paper in 1913 entitled "The Linear Arrangement of Six Sex-Linked Factors in Drosophila, as Shown by Their Mode of Association" (J. Exptl. Zoology, volume 14, pages 43-59.) Sturtevant provided experimental evidence that genes were organized in a linear fashion on chromosomes by quantitiative analysis of the frequency of crossing-over between two traits carried on the X-chromosome of the fruit fly. This series of questions demonstrates the type of genetic cross used by Sturtevant in this study.

Instructions: The following problems have multiple choice answers. Correct answers are reinforced with a brief explanation. Incorrect answers are linked to tutorials to help solve the problem.

1. Predicting the genotype of a female fly
2. Predicting the genotype of a male fly
3. A fly cross involving two X-linked traits
4. Genetic evidence for crossing over in male flies