A cross in Drosophila involved the recessive, X-linked genesyellow(y), white(w), and cut(ct). A yellow-bodied, white-eyedfemale with normal wings was crossed to a male whose eyes and bodywere normal but whose wings were cut. The F1 females were wild typefor all three traits, while the F1 males expressed the yellow-bodyand white-eye traits. The cross was carried to F2, and only maleoffspring were tailed
Phenotype - Male offspring
y + ct - 9
+ w + - 6
y w ct - 90
+ + + - 95
+ + ct - 424
y w + - 376
y + + - 0
+ w ct - 0
a) what is the genotype of F1 parents?
b) construct a map assuming the white is at locus 1.5 on theX-chromosome
Which gene is in the middle? answer white
yellow (y) cut (ct) white (w)
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Part C
The white gene is located at map position 1.5 on the Xchromosome, between yellow and cut. Use the datato determine the map positions of yellow andcut.
What is the map position of cut (ct)? Enteryour answer to one decimal place (example: 33.4 or 10.0).
20.0
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Part D
What is the map position of yellow (y)? Enteryour answer to one decimal place (example: 33.4 or 10.0).
0.0
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Part E
Were any double-crossover offspring expected? answer is yes
Were any double-crossover offspring expected?
yes no
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Part F
How many double crossover offspring were expected? how do i findthis number
Enter answer as a whole number (round up if necessary).
A cross in Drosophila involved the recessive, X-linked genesyellow(y), white(w), and cut(ct). A yellow-bodied, white-eyedfemale with normal wings was crossed to a male whose eyes and bodywere normal but whose wings were cut. The F1 females were wild typefor all three traits, while the F1 males expressed the yellow-bodyand white-eye traits. The cross was carried to F2, and only maleoffspring were tailed
Phenotype - Male offspring
y + ct - 9
+ w + - 6
y w ct - 90
+ + + - 95
+ + ct - 424
y w + - 376
y + + - 0
+ w ct - 0
a) what is the genotype of F1 parents?
b) construct a map assuming the white is at locus 1.5 on theX-chromosome
Which gene is in the middle? answer white
yellow (y) | |
cut (ct) | |
white (w) |
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Correct
Part C
The white gene is located at map position 1.5 on the Xchromosome, between yellow and cut. Use the datato determine the map positions of yellow andcut.
What is the map position of cut (ct)? Enteryour answer to one decimal place (example: 33.4 or 10.0).
20.0
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Correct
Part D
What is the map position of yellow (y)? Enteryour answer to one decimal place (example: 33.4 or 10.0).
0.0
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Correct
Part E
Were any double-crossover offspring expected? answer is yes
Were any double-crossover offspring expected?
yes | |
no |
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Correct
Part F
How many double crossover offspring were expected? how do i findthis number
Enter answer as a whole number (round up if necessary).