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AP BIOLOGY
HEREDITY
ACTIVITY #7
NAME_____________________
DATE___________HOUR_____
FRUIT FLY PROBLEMS
The letters and symbols used to represent genotypes in fruit flies are different that
what is used to represent the genotypes of other organisms. For this lab you will
need to use the following key when representing the genotypes of the flies involved
in the crosses:
KEY:
+
W
Wild (red) type
White eyes
SE
VG
Sepia (brown) eyes
Vestigial Wings
PROBLEM A:
CROSS BETWEEN FEMALE WITH WILD EYES AND A MALE WITH SEPIA EYES
P Generation
2
Female
Wild Eyes
Male
Sepia Eyes
Genotype:
Genotype:
F1 Generation
2
Female
Wild Eyes
N = 5012
Genotype:
Heredity Activity #7 page 1
Male
Wild Eyes
N = 4995
Genotype:
F2 Generation
Female
Wild eyes
N = 3676
Male
Wild eyes
N = 3748
Female
Sepia eyes
N = 1286
Male
Sepia eyes
N = 1272
1.
Be sure that you provide the genotypes for all flies in the diagrams on
previous page.
2.
What mutation(s) were you following in this cross? (NOTE: Wild type is not
a mutation. It is the normal condition in flies. The sex of the fly is not a
mutation either.)
_____________________________________________________________
3.
Examine the data for the F1 Generation and F2 Generation results. Make a
hypothesis about the pattern of inheritance in this cross by answering the
following questions:
a.
Is the cross autosomal or sex-linked?_______________________
Autosomal inheritance involves alleles on chromosomes other than the
sex chromosomes. Sex-linked inheritance involves alleles found on
the X chromosome. To answer this question you need to compare the
number of males with a certain characteristics (wild eyes for example)
with the number of females. If there is no significant difference
between the numbers would you expect the pattern of inheritance to
be autosomal or sex-linked?
b.
Is(are) the mutation(s) dominant or recessive?_________________
c.
Is the cross monohybrid or dihybrid?_________________________
To answer this question you need to consider the number of mutations
being tracked through the crosses.
Heredity Activity #7 page 2
4.
Using the key on page 1 and the answers to the previous question, construct
a Punnett square to predict results of the P (parental) cross and the F1 cross.
If you are sure that the cross is not sex-linked, you should combine
the male and female numbers for the same phenotypes.
P Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
F1 Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
5.
According to the Punnett square results, what are the expected phenotypic
ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked,
you should combine the male and female data for the same phenotypes.
CROSS
F1
F2
Heredity Activity #7 page 3
EXPECTED PHENOTYPIC RATIO
6.
Look at the results of the F2 generation. How many total flies were produced
in this cross?
_____________________________________________________________
7.
Calculate the number of individuals you would expect to be produced from
this cross. To do this you need to multiply the expected ratio (or percent) by
the total number of flies produced in the cross. If you are sure that your
cross is not sex-linked, you should combine the male and female data for the
same phenotype.
PHENOTYPES
8.
Expected Ratio or
Percent
EXPECTED NUMBER
Calculate the chi-square value for the F2 generation in the space below. You
must show all work.
2
2
χ =∑
(o − e)
e
χ2 = ___________
Heredity Activity #7 page 4
9.
Use the Chi-Square Distribution Table below to determine the percent
probability that the observed variation is due to random chance alone.
Degrees of freedom = _______________
% Probability =
_________________
CHI-SQUARE DISTRIBUTION TABLE
Accept Hypothesis
Reject Hypothesis
Probability (p)
Degrees
0.95 0.90 0.80 0.70 0.50
of
Freedom
1
0.004 0.02 0.06 0.15 0.46
2
0.10 0.21 0.45 0.71 1.39
3
0.35 0.58 1.01 1.42 2.37
4
0.71 1.06 1.65 2.20 3.36
5
1.14 1.61 2.34 3.00 4.35
10.
0.30
0.20
0.10
1.07
2.41
3.66
4.88
6.06
1.64
3.22
4.64
5.99
7.29
2.71
4.60
6.25
7.78
9.24
0.05
0.01
3.84
6.64 10.83
5.99
9.21 13.82
7.82 11.34 16.27
9.49 13.38 18.47
11.07 15.09 20.52
Was the deviation between the expected and observed data due to chance
alone?
_____________________________________________________________
How do you know?______________________________________________
_____________________________________________________________
11.
Based on the answer to the previous question, should you accept or reject
your hypothesis regarding the pattern of inheritance for this cross?
_____________________________________________________________
Explain._______________________________________________________
_____________________________________________________________
_____________________________________________________________
Heredity Activity #7 page 5
0.001
PROBLEM B:
CROSS BETWEEN FEMALE WITH WILD EYES & VESTIGIAL WINGS AND A
MALE WITH SEPIA EYES AND WILD WINGS
P Generation
2
Female
Wild Eyes
Vestigial Wings
Male
Sepia Eyes
Wild (normal) Wings
Genotype:
Genotype:
F1 Generation
2
Female
Wild Eyes
Wild Wings
N = 5003
Genotype:
Male
Wild Eyes
Wild Wings
N = 5080
Genotype:
F2 Generation
Female
Wild eyes
Wild wings
N = 2805
Male
Wild eyes
Wild wings
N = 2797
Female
Sepia eyes
Wild wings
N = 974
Male
Sepia eyes
Wild wings
N = 959
Female
Wild eyes
Vestigial wings
N = 956
Male
Wild eyes
Vestigial wings
N = 872
Female
Sepia eyes
Vestigial wings
N = 337
Male
Sepia eyes
Vestigial wings
N = 301
Heredity Activity #7 page 6
12.
Be sure that you provide the genotypes for all flies in the diagrams on the
previous page.
13.
What mutation(s) were you following in this cross? (NOTE: Wild type is not
a mutation. It is the normal condition in flies.)
_____________________________________________________________
14.
15.
Examine the data you collected form your crosses (F1 Generation and F2
Generation results). Make a hypothesis about the pattern of inheritance in
this cross by answering the following questions:
a.
Is the cross autosomal or sex-linked?_______________________
b.
Is(are) the mutation(s) dominant or recessive?_________________
c.
Is the cross monohybrid or dihybrid?_________________________
Using the key on page 1 and the answers to the previous question, construct
a Punnett square to predict results of the P (parental) cross and the F1 cross.
If you are sure that the cross is not sex-linked, you should combine
the make and female numbers for the same phenotypes.
P Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
Heredity Activity #7 page 7
F1 Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
16.
According to the Punnett square results, what are the expected phenotypic
ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked,
you should combine the male and female data for the same phenotypes.
CROSS
EXPECTED PHENOTYPIC RATIO
F1
F2
17.
Look at the results of the F2 generation. How many total flies were produced
in this cross?
_____________________________________________________________
Heredity Activity #7 page 8
18.
Calculate the number of individuals you would expect to be produced from
this cross. To do this you need to multiply the expected ratio (or percent) by
the total number of flies produced in the cross. If you are sure that your
cross is not sex-linked, you should combine the male and female data for the
same phenotype.
PHENOTYPES
19.
Expected Ratio or
Percent
EXPECTED NUMBER
Calculate the chi-square value for the F2 generation in the space below. You
must show all work.
2
2
χ =∑
(o − e)
e
χ2 = ___________
Heredity Activity #7 page 9
20.
Use the Chi-Square Distribution Table from question #9 to determine the
percent probability that the observed variation is due to random chance
alone.
Degrees of freedom = _______________
% Probability =
21.
_________________
Was the deviation between the expected and observed data due to chance
alone?
_____________________________________________________________
How do you know?______________________________________________
_____________________________________________________________
22.
Based on the answer to the previous question, should you accept or reject
your hypothesis regarding the pattern of inheritance for this cross?
_____________________________________________________________
Explain._______________________________________________________
_____________________________________________________________
_____________________________________________________________
PROBLEM C:
CROSS BETWEEN FEMALE WITH WILD EYES AND A MALE WITH SEPIA EYES
P Generation
2
Female
White eyes
Genotype:
Heredity Activity #7 page 10
Male
Wild eyes
Genotype:
F1 Generation
2
Female
Wild eyes
N = 5019
Genotype:
Male
White eyes
N = 5008
Genotype:
F2 Generation
Female
Wild eyes
N = 2579
Male
Wild eyes
N = 2454
Female
White eyes
N = 2545
Male
White eyes
N = 2467
23.
Be sure that you provide the genotypes for all flies in the diagrams on pages
10 and 11.
24.
What mutation(s) were you following in this cross? (NOTE: Wild type is not
a mutation. It is the normal condition in flies.)
_____________________________________________________________
25.
Examine the data you collected form your crosses (F1 Generation and F2
Generation results). Make a hypothesis about the pattern of inheritance in
this cross by answering the following questions:
a.
Is the cross autosomal or sex-linked?_______________________
b.
Is(are) the mutation(s) dominant or recessive?_________________
c.
Is the cross monohybrid or dihybrid?_________________________
Heredity Activity #7 page 11
26.
Using the key below and the answers to the previous question, construct a
Punnett square to predict results of the P (parental) cross and the F1 cross.
If you are sure that the cross is not sex-linked, you should combine the make
and female numbers for the same phenotypes.
P Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
F1 Cross:
_______________ x _______________
(female genotype)
(male genotype)
Punnett Square:
Heredity Activity #7 page 12
27.
According to the Punnett square results, what are the expected phenotypic
ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked,
you should combine the male and female data for the same phenotypes.
CROSS
EXPECTED PHENOTYPIC RATIO
F1
F2
28.
Look at the results of the F2 generation. How many total flies were produced
in this cross?
_____________________________________________________________
29.
Calculate the number of individuals you would expect to be produced from
this cross. To do this you need to multiply the expected ratio (or percent) by
the total number of flies produced in the cross. If you are sure that your
cross is not sex-linked, you should combine the male and female data for the
same phenotype.
PHENOTYPES
Heredity Activity #7 page 13
Expected Ratio or
Percent
EXPECTED NUMBER
30.
Calculate the chi-square value for the F2 generation in the space below. You
must show all work.
χ2 = ___________
31.
Use the Chi-Square Distribution Table from question #9 to determine the
percent probability that the observed variation is due to random chance
alone.
Degrees of freedom = _______________
% Probability =
32.
_________________
Was the deviation between the expected and observed data due to chance
alone?
_____________________________________________________________
How do you know?______________________________________________
_____________________________________________________________
33.
Based on the answer to the previous question, should you accept or reject
your hypothesis regarding the pattern of inheritance for this cross?
_____________________________________________________________
Explain._______________________________________________________
_____________________________________________________________
_____________________________________________________________
Heredity Activity #7 page 14