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Genetics Problem- fruitflies

  • #1

Homework Statement


A wild type fruitfly was crossed with another fruitfly whose phenotype was not recorded. They had progenies in the following ratios. 3/8 wild type, 3/8 ebony body, 1/8 vestigial wings and 1/8 ebony body and vestigial wing. If the genes are located on different chromosomes and ebony and vestigial wings are recessive characters find out the genotypes of the parents?

A. ee vgvg & e+e+ vg+vg
B. ee vg+vg & e+e vg+vg
C. e+e vgvg & e+e+ vg+vg
D. e+e vg+vg & e+e vg+vg

Ans: B


2. The attempt at a solution

I'm stumped and need some hints to begin solving from some point.
 

Answers and Replies

  • #2
Borek
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I admit I have not checked, but if you have no idea what to do writing all possible combinations down is typically the best starting point (some of them can be probably ignored immediately, others will produce different ratios).
 
  • #3
Ygggdrasil
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Since the ebony body and vestigial wing traits assort independently, you can break the problem down into first looking only at the ebony body phenotype and then examining the vestigial wing phenotype. What is the ratio of flies with wild type bodies vs ebony bodies? What type of cross would produce that ratio? What is the ratio of flies with wild type wings vs vestigial wings? What type of cross would produce that ratio?
 
  • #4
Sorry for the late response. Thank you so much!
I got it completely!

What is the ratio of flies with wild type bodies vs ebony bodies? 3:3 i.e. 1:1, a test cross, so e+e x ee.
What is the ratio of flies with wild type wings vs vestigial wings? 3:1 What type of cross would produce that ratio? Monohibrid second gen cross, vg+vg x vg+vg

Combining both the parental genotypes are: e+e vgvg+(wildtype) and ee vgvg+(ebony).
 

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