Drosophila F2 gen eration

1
Drosophila F2 generation

• Biol 3250
• Mar. 12-16, 2007

2
Counting Drosophila F2 generation

• Anesthetize flies and score phenotypes
• Score all possible phenotype combinations!
• for example, if your mutations were dumpy and
  sepia, you have four possible phenotype
  combinations
• wild-type
• wild-type eyes, dumpy wings
• sepia eyes, wild-type wings
• sepia eyes, dumpy wings

3
Counting Drosophila F2 generation

• Based on your hypothesis from 2 weeks ago and on
  the total number of flies that you count today,
  calculate an expected number for each phenotype
• For example, if you hypothesized that both sepia
  and dumpy are autosomal recessive, then you would
  expect to find the following
• 9/16 wild-type
• 3/16 wild-type eyes, dumpy wings
• 3/16 sepia eyes, wild-type wings
• 1/16 sepia eyes, dumpy wings
• Based on these expected numbers and your actual
  count, perform a chi square analysis to evaluate
  your hypothesis