Q: Data set summarizes F2 numbers from a cross between two, true-breeding Drosophila strains (P generation), which differ with respect to two traits. The gene alleles can be dominant or recessive, and autosomal or X-linked.
My data set is:
Wild type, females: 306
Purple eyes, females: 91
Purple eyes, tan body, males: 43
Wild type, males: 148
purple eyes, males: 47
tan body, males: 156
Answer the following questions based on the data set:
1. Assign genetic symbols to the genes and alleles involved.
2. Produce one genetic hypothesis about the mode of inheritance of the genes from your data set. For example, the allele for yellow eyes is X-linked and recessive and the allele for long legs is autosomal dominant. Include the expected phenotypic ratios in the P, F1 and F2 generations. (Note, for analysis it will be simpler to treat each gene separately, and formulate a genetic hypothesis for each gene)
3. Illustrate your genetic hypothesis using a breeding diagram or a table in which the P, F1, and F2 generations and their phenotypes and genotypes are clearly indicated. Include the expected (predicted) phenotypic ratios for the P, F1, and F2 generations.
4. Analyze whether the data fits your hypothesis by the Chi-square test. (keep in mind that you have to come up with a genetic hypothesis that both makes sense and will not be rejected. In order to test your genetic hypothesis, you must formulate a null hypothesis. More than one hypothesis may work for a given data set, but you are only required to show one)