1. Identifying genes that control wing shape in flies Gregory Campbell Central Catholic High School Pittsburgh

2. In narrow (nw) mutants the wing is narrow Wild-type narrow (nw)

3. The Nw protein is required to make the wing wide How does it do this? We don’t know how narrow protein functions It is secreted from wing cells - looks like a protein that binds to other proteins Nw protein nw mutant Wild-type

4. Wings during metamorphosis in the fly pupal stages Increasing age During metamorphosis in the wild-type pupa, normal wings become narrower when cells move in between each other.

5. Wings during metamorphosis in the fly pupal stages Increasing age In nw mutants the wings become too narrow when cells move in between each other too much.

6. Protein X: helps make the wing the right shape by making them move in between each other If Protein X becomes overactive the wing becomes narrow Possibility 1: Narrow binds to Protein X to suppress function Possibility 2: Narrow binds to protein Y, interacting to suppress to X function Nw protein Protein Y Protein X (overactive) Nw protein Reducing the amount of X in a nw mutant should make wing less narrow If Y exists, reducing Y in a nw mutant may make the wing more narrow Protein X Hypothesis Protein X

7. So how to do you find genes x and y? Test mutations in all the genes in the fly? Take forever! Alternative: Use Deficiencies (Df) Dfs = small deletions in a chromosome Each deletes a different region of a chromsome Each Df may include 10-50 genes 200 Dfs cover almost all of the chromosomes Df(2L)ED250

8. Studies done before I started: 18 Dfs identified that which make a narrow mutant wing narrower or wider, e.g. Df(2L)ED250 and Df(2L)N22-14 nw[D]/Df(2L)ED250 nw[D] Df(2L)N22-14 nw[D]/+

9. 24F-25A region of the chromosome Is one of these gene y? Deficiency Df(2L)ED250 makes the narrow wing narrower nw[D]/Df(2L)ED250 nw[D]/+

10. Test more Dfs in 24F-25A region

11. Method Cross nw[D] to Df Pick out nw[D]/Df flies Pull wings off and mount on microscope slides Take picture Measure length and width of wings Compare l:w of nw[D]/Df to nw[D]/+ Use statistical test (t-test) to find if difference is likely to be real

12. Results for 24F-25A region

13. Results on chromosome map Blue = interacts (makes wing narrower) Red = no effect (same as nw[D]/+)

14. Which gene?

15. Dp mutants have defective wings dp[olv1] wild-type Why dp mutant wings look like this is not understood Dp protein is very large and is found on the outside of cells Do dp mutants change the shape of nw mutant wings like the Df? (no Dp protein)

16. Do mutations in dp interact with nw? nw[D]/dp[olvR] Yes! nw[D]/dp[ov1] nw[D]/+ (50% Dp protein)

17. Conclusion Identified dp as a gene that interacts with nw Dp may be protein Y: results suggest Nw may function with Dp to stop the wing becoming too narrow Nw protein Protein Y Protein X Nw protein Protein X but it must be more complicated than this..

18. Shape changes in nw mutants are similar to those in vertebrate embryos Frog embryos Increasing age Convergent extension Wings during metamorphosis in pupa Increasing age Too much convergent extension?