Please submit to the Week 6 Experiment dropbox no later than Sunday midnight.
Component Expectation Points
Correctly perform and record the outcome of five monohybrid crosses
5
(Table 1).
Experiment 6 Demonstrate an understanding of the possible outcomes of
Exercise 1 monohybrid crosses with respect to genotypes and phenotypes
(Questions 1-2). 4
See Q #1
Experiment 6 Determine the correct parental gametes and conduct a dihybrid cross. 5
Exercise 2 Correctly evaluate the outcome of a dihybrid cross (Questions 1-2). 6
Correctly recognize one’s phenotype and assigns the correct genotype
4.5
(Table 2). See Table 2
Experiment 6
Exercise 3 Demonstrate an understanding of dominant and recessive traits,
genotype vs phenotype and homozygous vs heterozygous (Questions 5
1-6). See Q #6
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TOTAL 29.5 pts
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Experiment 6 Exercise 1: Monohybrid Crosses
rs e
ou urc
You will be conducting monohybrid crosses using fruit flies. Open in the following website:
Glencoe-McGraw Hill. No date. Punnett Squares
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http://glencoe.mcgraw-hill.com/sites/dl/free/0078759864/383934/BL_05.html
aC s
vi y re
Procedure
A. Open the above website and click on the VCR to listen to the introduction. Close the window
ed d
when done.
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B. Click on the Lab Notebook on the lab bench. A breeding scenario will be presented to you that
you will need to carry out. Here are the possible phenotypes and genotypes you will using:
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a. Normal wings (LL or Ll) or vestigial wings (ll)
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b. Gray body (GG or Gg) or black body (gg)
C. Enter the Scenario number in Table 1 below.
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D. Based on the Scenario, use the down arrows beneath the Parent 1 and Parent 2 boxes to select
the appropriate parents. Look carefully at the flies so that you know which ones to select.
E. Before proceeding, click on the Check Parents button. If necessary, make corrections. If you
are correct, the maternal and paternal alleles will be added to the Punnett Square.
Updated October 2013
This study source was downloaded by 100000805705997 from CourseHero.com on 11-03-2021 21:20:12 GMT -05:00
https://www.coursehero.com/file/18046658/BIO-Wk6-Exp-w-correct/
, F. Next, drag the correct allele combinations and the corresponding fly types to the boxes in the
Punnett Square.
G. When you are done, click on Check Offspring. If necessary, make corrections.
H. Record your data in Table 1 below. An example has been given, but note that the example is
not using the genotypes and phenotypes used in this exercise.
I. Click on Reset. Repeat steps B - H four more times for a total of five crosses. If a scenario is
presented that has already been completed, click Reset again. DO NOT REPEAT a given
scenario!
Note that the scenario number you need to record in the Table below is the number associated
with the specific scenario you completed.
Table 1. Results of crosses.
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Parent Genotypes Offspring Genotypes Offspring Phenotype
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Scenario # Parent 1 Parent 2 # % # %
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2 Rr 50% Rr 2 red 50% red
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Example Rr rr
rs e 2 rr 50% rr 2 white 50% white
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8 GG Gg 4Gg 100% Gg 4 gray flies 100%gray
2 Homo
2LL 50% LL Long Wing 50% Homo
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4 LL Ll
2Ll 50% Ll 2 Hetero 50% Hetero
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Long Wing
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2GG 50% GG 100% gray
6 GG Gg 4 gray flies
2Gg 50% Gg flies
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50% long
50% LL 2 long wing
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2 Ll wing
7 Ll ll 50% ll 2 vestigial
2 ll 50%vestigial
wing
wing
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2Gg 50% Gg 2 gray 50% gray
1 Gg Gg
2gg 50% gg 2 black 50% Black
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Questions
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1. Which type of cross gave you the greatest number of genotypes? Was the number of
phenotypes the same as the number of genotypes or different? If different, why (2 pts)?
LL/GG and Gg/Ll gave me the greatest number of genotypes. Yes the number of phenotypes as
well as gentotypes. No there wasn’t a difference.
Updated October 2013
This study source was downloaded by 100000805705997 from CourseHero.com on 11-03-2021 21:20:12 GMT -05:00
https://www.coursehero.com/file/18046658/BIO-Wk6-Exp-w-correct/