Purchase College, SUNY
General Biology I Laboratory

Drosophila Inheritance: Lab Report

For this exercise, you should write an individual lab report describing your conclusions about the P generation for your unknown cross, and supporting that conclusion with statistical analysis of the F2 generation.  The introduction should include the number of the unknown culture you were given, as well as a brief description justifying the use of these techniques to predict the phenotypes of the P generation which you have never seen.  The Methods secton is a brief description of what you received to begin the experiment, and the culture methods you used to obtain the F2 generation data.  Always mention what statistical methods you will be using to analyze the data.

Your data (the Results section) consists primarily of the number of offspring and phenotypes found in both the F1 and F2 generations.  The discussion will consist of your hypothesis for the P generation phenotypes, the resulting Punnett squares, and the chi square analysis.  If the p values show that your data deviates significantly from the expected values, discuss possible interpretations or reasons for the deviation.

Your report should include a Punnett square analysis to support your prediction ratios and numbers.  Normally, in a scientific report, you would only give the type of statistical analysis performed, and the significance (the p value).  For this exercise, please show the process you used to arrive at the chi square number (including the numbers you used for expected, observed, deviations, etc.), as well as stating whether it is significantly different from the expected, and the p value. Both Punnet Squares and the chi square statistical analysis may be shown in a table in Word, and included in the text of the report. If you prefer, you may do each in an Excell spreadsheet and attach it to your submission.

The Moodle website provides a space for your electronic submission of the report. Write your report in any word processor, proofread, and save a copy. Copy the text of your report (with tables if desired) and paste it into the provided space. Save other figures or tables in Excel97 (.xls) format, or Word97 (.doc) format - or 'rich text format' (.rtf) format - and submit that file separately in the provided space. It is best to make the file name include your own last name to ensure that it does not get mixed up with someone else (file name might be smith_fly_analysis.xls, or smith_drosophila_tables.doc, or smith_inheritance_data.rtf, for example).