Drosophila Genetics

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Drosophila Genetics

• Inheritance of Body Color
• B. Three Point Testcross

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Fruit Fly Egg and Larva
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Fruit Fly Pupa and Adult
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Inheritance of Body Color Phenotypes of Parents
Letter Gender Body Color
A Female Beige body
B Female Beige body
C Male Beige body
D Female Yellow body
E Male Yellow body
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Inheritance of Body Color Crosses

• A x C B x C D x C
• A x E B x E D x E
• Score each fly for gender and body color

Yellow
Beige
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Distinguishing Male and Female Fruit Flies

• Male body size is smaller than female
• Male abdomen is tapered and darker than
  female abdomen
• Males have sex combs at first joint on front legs

You MUST be able to see sex combs on any fly you
identify as male!
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Three Point Testcross
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Three Point Testcross
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Three Point Testcross Possible Phenotypes
Body Color Wing Length Eye Color
Beige Long Red
Black Vestigial Brown
Beige Vestigial Brown
Black Long Red
Beige Long Brown
Black Vestigial Red
Beige Vestigial Red
Black Long Brown
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Three Point Testcross F2 Offspring

• Score each fly for body color, wing shape and
  eye color.

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Wild Type Versus Mutants

• Body Color
• Wild type Beige
• Mutant Black

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Wild Type Versus Mutants

• Wing Shape

Wild Type Long
Vestigial
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Wild Type versus Mutant

• Eye Color
• Wild Type brick red
• Mutant Brown red-brown(slightly lighter than
  sepia)

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Nap Time
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How to anesthetize a fly
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Viewing the Fruit Fly
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Reference for Pictures

• Carolina Drosophila Manual (45-2620)
• Published by Carolina Biological Supply Company