- The student conducted a fruit fly experiment to observe inheritance patterns of mutants in the F1 and F2 generations. - In the F1 generation, 4 males exhibited the white eye mutation. The F2 generation showed wild type, white eye, vestigial wing, and combined mutants. - Chi-square analysis found differences between observed and expected phenotypic ratios, suggesting the results did not match expectations likely due to not reaching the target number of flies. - The experiment demonstrated Mendelian genetics and inheritance patterns but did not precisely match ratios likely due to insufficient sample size.

1. Jessica Olivares
11/22/2014
Bio 3103
Fly lab report
Fruit Fly Report
Hypothesis
In setting up the fruit fly experiment the predicted mutant phenotypes were to be
compared in the observed F1 generation and F2 generation. In order to make the appropriate
phenotypic ratios we based the F1 and F2 to generate two mutants that were used to set up the
parental cross. In the observed F1 generation the white eye mutant was located on the male
drosophila melanogaster. The following white eye mutation could be set up by the following
white type white eye female and a combination of wild type male with vestigial wings. Since
only the F1 generation was observed during the beginning of this experiment the cross between
the F1 generations for the given cross was identified for the P generation.
In the following F2 generation a new mutant was observed in both male and females, 2
different phenotypes the white eye gene was again observed following a new mutant; vestigial
wings. In predicting this outcome the suggested prediction for the following traits had to do with
the outcome that was created by setting up wild type females with white eyed males.
Suggested outcomes of the following genes could be the possible aspect that the two
genes assort independently and or dependently from each other. Both traits are located in
different chromosomes which have different locations in their according chromosome. Such as
the white eye gene is located on the X chromosome. On the other hand the white eyes mutation
is also a sex linked gene which can have a larger possibility for males to exhibit the white eye
gene trait due to where the gene is located on the chromosome.
For the given outcomes of the genes if predicted genes were autosomal than the
reciprocal crosses would generate a same F1 phenotype because the genes are carried on genes
that do not distinguish based on sex. On the other hand if the genes are different such as one is
autosomal and the other gene is sex linked than the following
genes would also create reciprocal crosses that generate different
F1 phenotypes because the genes carry different genotypes and
once crossed the number of phenotypes would be different
according to the overall phenotypic ratios.

2. Methods
For lab one the Drosophila melanogaster species was introduced by indicating the 3
principles of Mendel. The purpose of the lab was to introduce us to the basic structure and the
life cycle of fruit flies and the basic techniques of identifying fly mutants and wild type fruit
flies.
Lab one consisted of several different exercises that helped us identify and understand the
differences of fly mutants and wild type fruit flies. For exercise #1 we obtained a Carolina
Drosophila melanogaster manual. The required tools that we used included culture vessels,
plugs, medium; marking pencils or permanent pens, labels, fly nap, white sorting cards, fine
sorting brushes and a microscope were all used for this experiment.
The instructor showed us how to make a fly food vial and we prepared fly vials. We first
obtained disposable vials, we mixed an equal amount of fly food and distilled water. Then we
mixed gently until a homogenously blue food solidified. Then if necessary we wiped away
remaining liquid on the vial. After for exercise #2 we identified the life cycle of the fruit flies
and answered questions after that we set up groups of 3 members and obtained a wild type
Drosophila culture from front bench and observed under the microscope. After we also identified
the stage and the sex of the fruit fly. Then we learned to anesthetize adult flies and we placed
them under the microscope for further identification.
To anesthetize flies we obtained empty vial with foam stopper and added 2 drops of fly
nap to the inside of the foam stopper. Then we placed the foam stopper in vial. We then
transferred the flies in the empty vial, we removed the stopper/ vial and then gently tapped the
bottom of the Drosophila culture. Then we quickly removed the stopper from the culture and
placed the foam stopper on the napping chamber. Then watched and waited for about 60-90
seconds until fruit flies stopped moving and after that removed fruit flies from vials for
examination. Under the microscope we distinguished and separated male and female flies.
In exercise #3 we identified different fly mutants and repeated the process of anesthetize
to observe and compare from mutant to wild type fruit flies. For exercise #4 we reviewed
Mendel’s law of genetics, punnet square, chi square, monohybrid cross and Mendel’s dihybrid
cross.
For lab two the purpose of the lab was to observe the basic techniques of culturing flies
and set up a crosses between different fruit flies and to provide proper nomenclature. In this lab
we were given several exercises that consisted of table and information on how to help us
understand the techniques we will be using for the purpose of this lab.
In exercise #1 we learned the Drosophila nomenclature, based on the phenotype and the
gene was given a name. Then we used the genotype to track other genes at a time. For exercise
#2 we predicted cross outcomes by using two examples given to us in the unit file. Then we were
assigned two traits from the instructor and wrote down the crossing scheme and predicted the
phenotypic ratios in the given examples, generations. For exercise #3 our group of 3-4 people
obtained the fruit flies that were used to set up the F1 generation and for this exercise the F1 flies

3. were the offspring’s of an unknown P cross. At the end of this exercise the mission was to
identify the 2 mutants that were used in the original cross and to understand how they were set
up by breeding F1 flies and tracking the inheritance patterns. For this experiment we received a
vial with name of a cross and all the required information.
For lab three we conducted scientific methods to solve genetic crosses, which included
making a hypothesis, designing an experiment, carrying out the procedure and interpreting the
results. After the fly breeding, data collection and analysis my group discussed and collaborated
the importance of our data and proposed an explanation for alternative outcomes.
For this following lab we included the fly breeding techniques to help collect 1000 or
more flies. For this part we used two methods which included transferring flies into new vials.
Then examined flies for their phenotypes. For the first method if we did not need to examine
flies for their phenotype then we put them into a new vial so it can be separated from the new
vials to the new F2 generation. At the beginning of the lab we made several examinations of the
fruit flies and for 23 days our group monitored the flies during the appropriate days or at the end
of the Drosophila Melanogaster life cycle. During these 23 days we followed the breeding
patterns and collected the amount of fruit flies examined per day. Carefully each day we gathered
our data collected and at the end of lab we did a summary of the collected analysis.
Results
 About 10 days of data collection
 Data collected 11/11/2014-11/20/2014
 Observed F1 and F2 generation fruit flies
F1 Generation 11/11/2014
Male Female
Wild Type 24 31
White Eyes 4 N/A
Vestigial Wings N/A N/A
White Eye; Vestigial wings N/A N/A
Total Counted 28 31
The table above shows the constructed F1 generation with one mutant being recognized in 4
male fruit flies. The following mutant recognized was the white eye mutation. 28 counted males
with 4 being white eyes in the F1 generation. 31 counted females were counted in the F1
generation with all being classified as wild type.
F2 generation
Date
Counted
Vial
#
wild
male
wild
female
white
eyed
male
white
eyed
female
vestigial
male
vestigial
female
vestigial
white
male
vestigial
white
female Total
11/11/2014 SR 7 11 2 20
11/12/2014 1 3 3 2 8
JO 5 4 1 1 1 12

4. 11/13/2014 1 3 20 5 4 32
4:00pm 4 0
11/13/2014 SR 3 6 9
11/18/2014 1 8 21 5 2 4 40
11:15am 4 16 25 9 2 3 4 59
11/18/2014 1 0
7:30pm 4 3 6 9
11/18/2014 JO 52 24 6 5 6 1 94
11/18/2014 SAR1 27 65 27 3 17 1 140
11/18/2014 SAR2 15 60 15 90
11/18/2014 SR 19 42 7 2 4 74
11/19/2014 1 9 4 9 3 25
2:15pm 4 7 6 4 17
11/19/2014 JO 10 15 4 3 32
SAR 10 11 5 2 4 1 33
SR2 16 8 9 1 1 35
SR6 7 10 12 29
11/20/2014 1 16 5 11 6 1 39
11:10am 4 14 8 14 4 2 42
11/20/2014 JO 1 1 1 3
SAR 1 1 2
SR2 2 4 1 7
SR6 2 6 10 18
TOTAL 254 357 160 15 22 52 7 2 869
overall
total
wild 611
white 175
vest 74
vest/white 9
In the above table the F2 generation was summarized by counting the apparent different fruit
flies. 4 classifications were categorized in the following table. Wild type, white eyes, vestigial,
and vestigial and white eyes were counted for each male and each female fruit fly at the end the
overall total was given.
The Following tables are all constructed F2 phenotypic ratios and Chi square analysis of the F2
generation.
Phenotypes Expected
Overall
Phenotypic
Ratio
Expected
Phenotypic ratio for
Females
Expected
Phenotypic Ratio
for Males
Wild Type 6/16 3/8 3/8
White Eyes 6/16 3/8 3/8
Vestigial Wings 2/16 1/8 1/8
White eyes; vestigial wings 2/16 1/8 1/8

5. Expected Overall Phenotypic Ratio
Phenotypic
Class
O E O-E (O-E)^2 (O-E)^2/E
Wild type 611 325.875 285.125 81296.26563 249.4707039
White eyes 175 325.875 -150.875 22763.26563 69.85275222
Vestigial
wings
74 108.625 -34.625 1198.890625 11.03696778
White eyes;
Vestigial
Wings
9 108.625 -99.625 9925.140625 91.3706847
869 Chi Square= 421.7311086
Expected Phenotypic Ratio for Females
Phenotypic
Class
O E O-E (O-E)^2 (O-E)^2/E
Wild type 357 133.875 223.125 49784.76563 371.875
White eyes 15 133.875 -118.875 14131.26563 105.5556723
Vestigial
wings
52 44.625 7.375 54.390625 1.218837535
White eyes;
Vestigial
Wings
2 44.625 -42.625 1816.890625 40.71463585
426 Chi Square= 519.3641457
Expected Phenotypic Ratios for Males
Phenotypic
Class
O E O-E (O-E)^2 (O-E)^2/E
Wild type 254 166.125 87.875 7722.015625 46.48316403
White eyes 160 166.125 -6.125 37.515625 .22582769
Vestigial
wings
22 55.375 -33.375 1113.890625 20.11540632
White eyes;
Vestigial
Wings
7 55.375 -48.375 2340.140625 42.25987585
443 Chi Square= 109.0842739

6. Discussion
For the given F1 cross the inheritance pattern of the given fruit flies was identified as a
white eyes and vestigial wings mutation. Two different traits that carry different genes in each
phenotype. As a reference to my chi-square values of my analysis I got 421.731 for the overall p
value. 519.364 For male p value and the 109.084 for the female p value analysis. The concluded
chi-square analysis proposed that because of the variation between the observed and expected
results is due by chance. The chi square analysis suggest that the F2 analysis is not consistent
with the phenotypic ratio. Although many of the phenotypic outcomes are seen but the collected
data is not accurately statistically being measured.
There is many differences between the expected number and the observed number in
regarding to the data collected. In this experiment 1000 fruit flies was not reached and that made
have unbalanced the appropriate phenotypic ratios and therefore the following results did not
match the chi-square analysis. Although we did not get what we expected for our F2 generation
we concluded that the inheritance patterns did not regulate the correct observed and expected
results. The ratio’s obtained from the following dihybrid cross concluded that that the F2
generation had a probability of the P crossed mutants being a white eyes and vestigial wings as
suggested in our hypothesis.
Although during my fly breeding my group did not reach to 1000 fruit flies and the only
problem I could understand is that not getting enough flies in your F2 generation could basically
interrupt and could give you a different inaccurate phenotypic ratios which could lead to an
uncertain P value.
In this experiment I learned how to review the principles of Mendel’s laws of genetics
which included using a punnet square, chi square analysis, and dihybrid crosses. In addition I
have learned how to conduct a fruit fly experiment by observing the F1 generation and
interbreeding them to yield an F2 generation. With the following techniques I have also learned
to analyze the experimental data to create a hypothesis. For this lab I was able to understand how
sex linkage genes assort independently and how either male or female can have a higher
probability to acquire that gene due to the location of the chromosome. If it was possible I would
think of taking this experiment to the next level by studying the F3 generation as well to observe
if it creates a new mutant trait where I could study the inheritance patterns and identify the
possibility of developing a new trait in each generation and how often a mutant trait occurs.