1. Thomas D. Kocher Department of Biology BSCI 338K Pigmentation Projects

2. Diversity of Color Patterns www.malawicichlids.com

3. Vertebrate pigment cells Endotherms (mammals, birds) –‘Melanocytes’ Ectotherms (fish, reptiles, amphibians) –‘Melanophores’ –Xanthophores –Iridophores

4. Epinephrine treatment

5. Iridophores

6. Guanine platelets Structural interference

7. Origin of the neural crest

8. Derivatives of the neural crest

9. NC migration pathways

10. Zebrafish mutants

11. Specification of pigment cells

12. Embryonic and adult melanophores

13. Model for chromatophore development from zebrafish NC (Curran et al. 2010)

14. Mother superior mutation Defect in foxd3 expression

16. Obelix mutation alters pattern

17. Zebrafish and cichlids compared

18. Metriaclima mbenjii vs. M. zebra

19. Standardized photos

20. Image analysis

21. Cell counts

22. Xanthophores in pelvic fin

23. Pigment traits in hybrids

24. Melanochromis auratus

25. Regeneration assays Figure 16. Regeneration of Metriaclima zebra fin at 2, 4 and 6 days post-amputation. Figure 17. Xanthophores in the regenerating caudal fin of a male M. saulosi.

26. Cell interactions Figure 18. Pigment patterning in the caudal fins of a) Aulonocara baenschi, b) Metriaclima mbenjii, c) Labeotropheus trewavasae, d) Metriaclima 'kompakt'.

27. Cell density Figure 19. Iridophore distribution changes with xanthophore density. Figure 20. Ontogenetic changes in the patterning of M. lombardoi.

28. L-DOPA assay for undifferentiated melanophores

29. Breeding biology Salzburger et al. 2007

30. Sexual dimorphism M. zebra masinjeM. zebra Nakantenga Male Female

31. Normal ‘BB’ female Orange-blotch ‘OB’ female QTL Is intersexual selection the whole answer? Reade B. Roberts

32. How many fish do you see?

33. OB is cryptic against some backgrounds

34. Loss of melanophores in OB

35. Family mapping

36. Association mapping Microsat genotypes aaAa 450 540

37. C D 100 km A Tetraodon Chr11 (Mb) M.zebra Makonde M.zebra ‘blaze’ Manda M.xanstomachus Nankoma Tropheops sp. Thumbi West L.trewavasae Thumbi West Lake-wide mapping panel LOD A B B C D E E Tetraodon Chr11 (Mb) F

38. Single OB haplotype in Malawi

39. OB allelic series

40. OB males are ugly! Females Males BB OB

41. A new sex chromosome Dominant OB mutation provides female crypsis OB reduces male mating success Divergent selection in males and females (genetic conflict) Selection favors mutations that create a dominant female sex determiner (W) near OB New sex determining system evolves: W OB Z femalesZZ males

42. Choosing a Project Choice of project starts with your interest Next step is to read the relevant research proposals (on the class wiki) Then schedule a meeting to talk with me about it Anytime - dig into the literature to see what others have done

43. Project Opportunities: Pigmentation Perform association studies of candidate genes Characterize pigment cell development from the neural crest Characterize differences in development among species Fine map genes controlling pigment variation Experimentally manipulate pigment cell populations during development or regeneration Annotate candidate pigmentation/neural crest genes in the cichlid genome sequence.