Tentative Laboratory Schedule, Fall 2002
Out-of-Class Preparation: Most of the labs will take the full three hours, especially on days on which you must separate and count the different classes of progeny from a cross. To use your lab time most efficiently and to avoid making costly mistakes, it is essential that you come to the lab prepared to do the work. At minimum, you should read the lab assignment prior to coming to class. You may also find it helpful to do background reading in the genetics textbook on the specific topic covered. There will be both announced and unannounced quizzes in lab. You should also expect to come to lab outside of your assigned "lab slot".
**** The nature of doing biological experiments is that organisms can be unpredictable; therefore, doing certain experiments properly will require your presence outside of class time. You will have access to the building and to the lab on weekends.
Lab Report Guidelines
1. Introduction. This should include a clear statement of the purpose of the experiment. Why are you doing the experiment? What genetic principles are you testing? What are your starting assumptions? This section should also contain a brief introduction and general description of the experiment you are reporting. You should include the genotypes (when known) and a description of the phenotypes of the stocks that were used in the experiment. You should state what criteria will be used to analyze the results of your experiment. For some of the reports a paper (or papers) related to the subject of the experiment will be assigned that you will be required to read and cite in your introduction.
2. Methods. This should be a brief specific description of what you actually did. Show all crosses made. You should give the number of flies of each sex you mated and their phenotype and genotype (if known). You should furnish a brief chronological record of the cross. Include any other pertinent information about how the experiment was conducted. Be sure you report exactly what you did and not what the Lab exercise handout said you were to do. These may differ since sometimes we have to modify the way crosses were set up.
3. Results. Show your numerical results in tabular form. Construct a simple table showing each phenotypic class and the associated genotypic class(es). Your tables must be clearly labeled. This section should also include, in tabular form, any statistical test you may have applied to your data. The interpretation of your data and interpretation of any statistical test applied to the data should appear in the next section (Discussion and Conclusions) of the lab report. Please Note: It is ESSENTIAL that you accurately report your findings and not manufacture data to fit preconceptions. The greatest advances in science occur when a careful researcher gets reproducible data which conflict with accepted notions. You will be graded on how you analyze and interpret your data-not on whether it agrees with your expectations.
4. Discussion. This section reports the importance of your results and state any conclusions. This is where you analyze and interpret your results. Do your data confirm or conflict with your initial expectations? Sometimes results do not turn out as you expect. Propose a genetic mechanism to account for any strange results. Was your sample size sufficiently large to give you confidence in your numbers? If several crosses were done, explain why the results of each one were similar to or different from the others. If you were given a coded vial of unknown genotype, report the identity of your unknown and the basis for your conclusion. When appropriate, use a statistical test to support your conclusions. In all cases, in this section you should present clearly and thoroughly all evidence that support your conclusions.
5. References. References should be listed in alphabetical order, in standard format.
Tips: Lab reports do not need to be lengthy. State your ideas clearly and concisely. Do not be verbose. The best scientific writing is clear and concise. The following articles offer helpful hints for writing scientific papers:
You are expected to use a word processor for the text and tables of your reports. If you do not know how to use a word processing program to generate tables, please let me know and I will show you how to do this. Please allow a one-inch margin for all page edges and double space all reports. For each report include a Cover Page with your name and the title of the report.
Spelling and grammar are important. Most word processors have a spelling checker. Use it! If you are not using a word processor or your word processor does not have a spelling checker, refer to a dictionary. Please note especially that the genus of the fruit flies we will be using for most of our experiments is Drosophila, not Drosophilia.
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