Welcome Back from Break

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Welcome Back from Break
This may have been your life on break
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This may be your life on Tuesday
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This is what we are returning to in L319
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Great Job Keep up the good work!!!
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Remember wit trait found in the A strain
Genotype 50 wit/ 50 wit/y Phenotype
females 100 WT (red) males 100 white
eyes
Genotype 25 wit/wit 25 wit/ 25
wit/Y 25 /Y Phenotype 50 white
eyes 50 WT (red)
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Other Direction
Genotype 50 wit/ 50 /y Phenotype
females 100 WT (red) males 100 WT
(red)
Genotype 25 wit/ 25 / 25 wit/Y 25
/Y Phenotype Males 50 WT 50
white Females 100 WT (red)
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What about hsy?
Genotype 100 hsy/ Phenotype 100 WT (red
eyes)
Genotype 25 hsy/hsy 50 hsy/ 25
/ Phenotype 25 hershey eyes 75 WT (red
eyes)
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What of the flies in the F2 generation should
have hershey eyes if wit is epistatic to
hsy? From the following crosses Po A female
X hsy male F2 males 50 white eyes, 50 WT
(red) F2 females 50 white eyes, 50 WT
(red) Po hsy female x A male F2 males 50
white eyes, 50 WT (red) Frequency white eyes
0.5 Frequency hershey eyes 0.25 of flies
with hershey eyes 0.50 x 0.25 0.125 or
12.5 From the F2 females from Po hsy female x
A male No white eyed flies, no epistasis 25
of flies should have hershey eyes
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Thus a white eye fly could be 1. hsy/hsy 2.
hsy/ 3. / How can we find out the hsy
genotype of a white eye male fly?
Can set up another cross F2 white-eyed male x
hsy female Will you see any white eyed flies in
the offspring?
No
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What are the possible phenotypes if the F2 male
genotype is
Genotype 100 /hsy Phenotype 100 WT
(red) Genotype 50 hsy/hsy, 50
/hsy Phenotype 50 hershey eyes, 50 WT
(red) Genotype 100 hsy Phenotype 100
hershey eyes
Unfortunately we dont have any live F2 male
flies to set up these crosses.
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Will look at the genotype of frozen F2 white-eyed
males using a different technique to
differentiate the Hsy and hsy alleles Polymeras
e Chain Reaction (PCR)
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Genotype 25 - 1425/ 1425 50 - 750/
1425 25 - 750/ 750
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Remember the sht trait found in A strain This
trait is found on Chromosome 2 The scores of F2
Data from both reciprocal crossed showed
that 48 out of 2870 flies were scored to have
both hershey eyes and short wings? Is this
possible?
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Remember Male flies do not undergo
recombination
Do you see hershey, short flies? No
How can you explain the data?
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Experiment 4 Tetrad Analysis Lets go over one
Gene Pair Calculation
PD NPD TT Total
His-Leu 124 3 68 195
His-Ura 43 41 108 192
His-Ino 37 36 115 188
Leu-Ura 67 73 48 188
Leu-Ino 28 40 114 182
Ura-Ino 37 39 118 194
His-MAT 49 22 112 183
Leu-MAT 52 7 117 176
Ura-MAT 34 29 120 183
Ino-MAT 32 30 114 176
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1. Do PD NPD? PD 67 NPD 73 Total
140 ?2 (67-70)2 (73-70)2 0.26 lt 3.84
- Can not reject Null Hypothesis 70
70
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2. Do PDNPD4TT? PD 67 NPD 73 TT 48 Total
188/6 31.3 ?2 (67-31.3)2 (73-31.3)2
(48-125.3)2 143.9 gt 5.99 Reject Null
Hypothesis 31.3 31.3
125.3
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• Calculate Centromere Distance
• Total Centromere Distance 48 x 100
  12.7
• 2(188)
• Given Ura is 8 cM from its centromere
• Distance of Leu from its centromere 12.8 cM 8
  cM 4.7