Probability

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					Genetics and Heredity                                                                   Name: _______________________
                                                                                      Partner: _______________________



      INVESTIGATION: LAWS OF PROBABILITY AND GENETICS
    PURPOSE:

      The purpose of this laboratory experience is to apply the laws of probability to heredity and genetics. The laws of
      probability will be demonstrated using a coin toss, and then applied to the result of a cross between two individuals.
      The coin toss will be used to predict offspring gender and monohybrid crosses that follow Mendelian genetics. You
      will observe Mendelian traits that you possess, and compare to class members.

      MATERIALS:

               •    Coins
               •    Labels/masking tape
               •    Marker
               •    Lab sheet/ data tables

    PROCEDURE
      1.   Use the laws of probability to predict the                7.  Use the Punnett square to determine the possible
           outcomes of a coin toss with coin for 10 and 50               outcomes for the following cross: Tt x Tt.
           tosses. Record predictions in data table.                 8. Coins can be used to represent traits that follow
      2.   Toss the coin 10 times. Record results in data                Mendelian genetics. Label two coins as follows:
           table 1.                                                      T on one side of both, and t on the other side of
      3.   Toss the coin 50 times. Record results in data                both.
           table 1.                                                  9. Toss both coins 10 times, record results in data
      4.   Use the Punnett square to predict the gender                  table 3.
           outcomes of 10 trials, 50 trials. Record results.         10. Toss both coins 50 times, record results in data
      5.   The coins can be used to represent the genes that             table 3.
           will determine the gender of offspring. Label             11. Obtain a list of Mendelian traits that appear in
           two coins as follows: X on both sides of coin 1;              humans from your teacher. Determine which
           X on one side of coin 2; Y on the other side of               traits are present in each student, and record in
           coin 2.                                                       class data chart.
      6.   Toss both coins 10 times and record results; toss
           50 times and record results in data table 2.

    PRE-LAB QUESTIONS
      1) Define the term probability.



      2) How can you relate probability and Punnett squares?



      3) How can you relate probability and genetics?



      4) How can a coin toss be related to genetics and Punnett squares?




Acton-Boxborough Regional High School                                               Due Date: ______________________
      Predictions:
      1. The probable outcome of a coin toss 10 times is _________ heads and ___________ tails.

      2. The probable outcome of a coin toss 50 times is _________ heads and ___________ tails.

      3. Gender                    % male 10:____________ % female 10_______________

                                   % male 50:____________ % female 50_______________




       4.   Tt x Tt predictions:                         Phenotype %:
                                                         Phenotype ratio:

                                                       Genotype %:
                                                       Genotype ratio:




    DATA
                                                     DATA TABLE 1

                                     # Heads              # Tails              % Heads            % Tails

            10 Tosses


            50 Tosses


                                                     DATA TABLE 2

                                      # XX                # XY                 % Female           % Male

            10 Tosses


            50 Tosses




                                                     DATA TABLE 3
Acton-Boxborough Regional High School
                                    # TT             # Tt             # tT                 # tt

            10 Tosses


            50 Tosses



                                                 CLASS DATA
                               Genotype/      Your Geno/    Class #           Class #    % Class with
             Trait             Phenotype      Phenotype    Dominant          Recessive    Dominant
                                                                                            Trait

       Bent Little Finger      BB, Bb: Bent
      (Bent is Dominant)       bb: straight

      Attached Earlobes
   (Unattached is Dominant)

     Hitchhikers Thumb
   (Non-Hitch is Dominant)

       Tongue Rolling
    (Can Roll is Dominant)

      Mid-Sagittal Hair
  (Hair Present is Dominant)

       Facial Dimples
   (Dimples are Dominant)

   Widow’s Peak Hairline
 (Widow’s Peak is Dominant)

          PTC test
  (Taste Bitter is Dominant)




     DISCUSSION
Acton-Boxborough Regional High School
       1.   Did your prediction match your results when you tossed the coin 10 times, 50 times? Explain.




       2.   Do you think that your percentages would have been closer to 50% if you tossed the coin 100 times? 500
            times? Why?




       3.   How does tossing the coins relate to how the gender of offspring is determined?




       4.   Is the male or female in humans responsible for determining gender? Explain.




       5.   Do your results match your predictions for gender? Explain.




       6.   How does tossing two labeled coins resemble how traits are determined in a monohybrid cross?




       7.   Do your results match your predictions for monohybrid cross Tt x Tt? Explain.




       8.   What are the genotype and phenotype ratios for your actual tosses for Tt x Tt?




       9.   With regards to the class data on Mendelian traits, would you expect to see more of the dominant or recessive
            traits show up in your classmates? Explain. (Hint: discuss genotypes, phenotypes, and predictable ratios).




       10. Is your class a good sample of the general population? Why or why not?




Acton-Boxborough Regional High School

				
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