Scholars Biology 3 Genetics Lab Report Searching for Correlations Between Phenotypes

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  • Scholars Biology 3Genetics Lab ReportSearching for Correlations Between Phenotypes

  • Refer to your syllabus for a more detailed description of items to be included in the lab report.

  • Components of the Lab ReportPurposeMethodsResultsDiscussionLiterature Cited

  • PurposeDescribe why the experiment was done Identify the hypotheses being tested --1 hypothesis for simple inheritance--1 hypothesis for complex inheritance--2 hypotheses for taste perception

  • Hypothesis for Simple InheritanceIf the dominant and recessive alleles are present in equal frequencies, this Punnett square represents the ratio of expected offspring for the whole population. E e EEEeEeee75% free earlobes 25% attached earlobesChoose any trait (EXCEPT short index finger) and determine whether the alleles are present in equal frequencies. (See p. 95 for details.)

  • Hypothesis for Complex InheritanceMultigenic Traits often show a range of phenotypes that approaches a normal distribution for numbers of individuals with each phenotype. For our experiment: Determine whether we see a normal distribution of heights with different central values for males and females.

  • Hypotheses for Taste PerceptionDetermine whether there is a relationship between 1. Supertaster and PTC-tasting phenotypes 2. Supertaster phenotypes and any ONE of the following: Gender Preference for Brussels sprouts Preference for Cheese Preference for Black coffee Preference for Dark chocolate

  • MethodsProvide a brief description of the techniques, materials and/or equipment used in the experiment. Emphasize how the methods accomplish the purpose given in the previous section. Focus on the determination of the phenotypes that are represented in your hypotheses, rather than all the traits tested. DO NOT write this section as a step-by- step guide for repeating the experiment. DO write it as a summary of the experimental procedure in past tense.

  • ResultsPresent your experimental data in this section. Introduce the reader to the data with a brief description that refers to the content of specific figures or tables. Choose the most appropriate format for each type of data presented. Simple Inheritance: Table or HistogramComplex Inheritance: Line GraphTaste Perception: Table or Histogram

  • ResultsEssential elements of a line graph or histogramPut a label and specify the units on each axis Make the plotted points or bars clearly visibleConnect related points by a best-fit lineInclude a key to identify different lines, bars Provide a caption BENEATH the graph or histogramBrief descriptionTitleNumber consecutively from Figure 1

  • Graphing the Data for Complex InheritanceNumber of StudentsHeight (cm)Male AverageFemale AverageClass AverageFigure 1: Distribution of Heights in a Scholars Biology 3 Class During Fall Semester 2003. Heights of 25 students were grouped into the size categories shown.

  • Displaying Data in a Histogram Percent of StudentsFigure 2: Frequency of Tongue-Rolling Trait in a Scholars Biology 3 Class During Fall Semester 2003. Phenotypes of 25 students were determined by visual observation. Tongue-Rolling Phenotypes




    Can't Roll

    Weds F03

    Number of Students% of StudentsHeight for MalesHeight for FemalesHeightMalesFemalesTotal

    Bent130.52170143< or = 14911

    Not Bent120.48170155150-1540



    Not attached150.60177158165-16922


    Tongue Rolling180.72180160.5175-179213

    Can't Roll70.28196162180-18411


    Widow's Peak60.24165190-1940

    No Peak190.76166195-19922

    170> or = 2000

    Left Thumb Up140.56171

    Right Thumb Up110.44174


    Left Arm Up110.44179

    Right Arm Up140.56Total1615Ave Male179.4

    Hitchhiker's Thumb180.72Total2612.5Ave Female163.3

    Not Hitchhiker70.28


    Middigital Hair110.44

    No Hairy Digits140.56

    PTC Early Taster130.52

    Late Taster50.20


    Can't Roll0.28

    Pigmented Iris220.88

    Blue Iris30.12

    Short Index Finger190.76

    Long Index Finger60.24

    Round Chin210.84

    Square Chin40.16

    Student #GenderPapillae NumberPTC PhenotypeLike Brussels Sprouts?Like Cheese?Like Coffee?Like Dark Chocolate?







    7malesuper (25)non-tasternononoyes







    14femalenon-taster (6)lateyesyesnono

    15malenormal (16)earlyyesyesyesyes

    16femalenormal (14)earlyyesyesnoyes

    17femalenormal (10)earlynoyesnono

    18malenormal (15)earlyyesyesyesyes

    19femalenormal (18)earlynoyesyesyes


    21femalenormal (13)latenoyesyesyes










    Weds F03


    Can't Roll

  • ResultsEssential elements of a tableProvide a caption ABOVE the tableTitleBrief descriptionPresent the data in clearly labeled columns and rows Provide labels and units of measure if applicableNumber consecutively from Table 1

  • Displaying Data in a Table Table 1: Frequency of Mid-Digital Hair in a Scholars Biology 3 Class During Fall Semester 2003. Phenotypes of 25 students were determined by visual observation.

    PhenotypePercentageMid-digital Hair0.44No Hairy Digits0.56

  • Discussion Present your interpretation of the results in this section. Draw conclusions that are based on the experimental evidence. Discuss whether or not the original hypotheses were supported by the data. Explain any discrepancies in your data.Elaborate on the biological implications of the results.* Relate your results to existing scientific knowledge.* *See Dr. Colavitos Other Links Web Page for more information on Supertasters.

  • Literature CitedInclude ONLY references cited in your report. To cite references in the text, use the format (Author, year).In the literature cited section, use the following format: For journal: Author, year, Title, Journal Name, volume number and pages For book: Author, year, Title, Publisher and City of publication For Web Page: URL and Date Accessed

  • Length of Each Section Purpose: 1-2 paragraphsMethods: 1 pageResults: 1 page + figures and tablesDiscussion 1-2 pagesTOTAL LENGTH: 3-5 pages of written materialFigures and tables should be included on additional pages.