BIOLOGY 50-554 (GENETICS ) LABORATORY SYLLABUS

I. GENERAL INFORMATION:

Out-of-class preparation

Many 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 a minimum, you should have read the Lab exercise handout. You may also find it helpful to do background reading in a genetics textbook on the specific topic covered.

Mental organization is critically important because you will usually be working on several different experiments each week. We will begin a new experiment most weeks, but because the crosses often take a month to six weeks to complete, there is extensive overlap between experiments. A schedule of weekly activities will be provided to help you organize your experiments.

Correlation with class info

The genetics laboratory experience is not a separate course unrelated to the lecture component. One of the goals of the laboratory exercises is to help you relate the material covered in lecture with actual experimental techniques. Thus, it is important that you do the background reading for each lab. There may be occasions when an experiment is started before the topic is covered in lab. However, since most experiments will take several weeks, the topic will certainly be covered before the lab report is to be written. Also, the principles behind each lab will be introduced in the laboratory exercise handout, and we will talk about them at the beginning of each lab period.

In-class record keeping

To intelligently analyze and write about your experiments, it is critical that you keep careful records of the crosses you make and the results you obtain from these crosses. You will need to carefully record the phenotype, the genotype, the sex and numbers of flies, and any other pertinent information for each experiment. You must understand what traits you are scoring for each cross and carefully record the results. Once you have dumped a group of flies into the ethanol morgue you cannot change your mind and retrieve them to check some point. Also, some weeks you will be pressed for time to count progeny from several different crosses. Only days later will you have an opportunity to sit down and carefully review your numbers and think about the results. If you then discover that your numbers make no sense or you have somehow confused the results for different experiments, it will be impossible to go back and check for the mistake you made.

Lab housekeeping

At the end of each lab period clean your work area. This includes putting away all the items that you used (microscopes, etc) and wiping down your work area.

Lab partners

Lab partners will be randomly assigned. This is not an attempt to keep you and your best buddy from being partners; instead, it is meant to simulate the REAL WORLD where one does not always get to choose with whom he or she will collaborate. It is essential that you develop skills that are related to working with other people. Thus, you and your lab partner will work together and turn in joint lab reports. Please note that this should be a collaborative event and if you do not do your "share" of the work, you should not sign the pledge at the end.

II. LAB REPORTS

For some labs, you will be required to prepare a formal write up, whereas for other labs you will complete an informal worksheet. For those labs that have a formal write up, the following format should be followed.

A. Lab reports should have the following format:

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 and Conclusions. This section reports the importance of your results. 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.
   
   Although these are formal lab reports this does not mean they should be lengthy. State your ideas clearly and concisely. Don’t be verbose. The best scientific writing is clear and concise. The following articles that offer helpful hints for writing scientific papers are on reserve in the library :
   
   Mack, R. N. 1986. Writing with precision, clarity, and economy. Bulletin of the Ecological Society of America 67: 31-35.
   
   Moore, Randy. 1991. How we write about biology. American Biology Teacher 53 (October): 388-89.
   
   Spector, Thomas. 1994. Writing a scientific manuscript. Journal of Chemical Education 71 (January): 47-50.
   
   Wilkinson, A. M. 1992. Jargon and the passive voice: prescriptions and proscriptions for scientific writing. Journal of Technical Writing 22(3): 319-25.

B. Presentation

We live in a computerized world, and so it is essential that you become well versed at using computers. Thus, you will be 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. Also, If you do not have access to either your own computer or for some reason you cannot use Southwestern’s computing facilities, please see me at the beginning of the semester and we will make other arrangements. Since the computer labs may often be busy, it will be necessary to plan carefully. A late lab report will not be excused from penalty because of poor planning.

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.

C. Spelling and grammar

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.

NOTE: 1) The word, "data," is plural. Thus, "data are" is the correct form. ("Datum" is the singular.) 2). The scientific name for organisms should be underlined or appear in italics, e.g., Drosophila or Drosophila.

III. And last but not least…….GRADING:

The laboratory component of Biology 50-554 will be worth 25% of your total grade for the course. The lab grade will be determined by your scores on the formal lab reports and the lab worksheets as follows:

Please note that although formal lab reports are not required for every lab session, lab attendance is mandatory at every session. If you can not attend a lab, please contact me. Also, any information covered in lab is fair game for lecture exams. Finally, late lab assignments will NOT be accepted.

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Last updated on 12 May 2009