Speciation and phenotypic evolution are two important causes of biodiversity.  The goal of research in my lab is to characterize the genetic and developmental bases of these two evolutionary processes at the molecular level.  We use the fruit fly, Drosophila, and the damselfly, Enallagma, to understand how evolutionary change gives rise to phenotypic differences between closely related species.  Our work is fundamentally interdisciplinary, integrating molecular genetics, developmental biology, cell biology, and evolutionary biology.

Our current research focuses on two primary questions:

·         What is the molecular basis of divergence in reproductive structure morphology between species?  We have fine-mapped several genomic regions that have large phenotypic effects on morphological variation, and we are currently pursuing functional studies to identify the genes that specify species-specific morphologies and understand how change at these loci directs development to give rise to morphological differences. In particular, we are focusing our efforts on novel proteins that specify variation in sex-specific cell and tissue growth. 

·         Do species-specific differences in reproductive structure morphology contribute to reproductive isolation?  We are investigating the contribution of genital morphology to sensory reproductive isolation by testing the consequences of interspecific variation in genital morphology on male reproductive success and female behavior. In conjunction with these studies, we are currently pursuing experiments aimed at understanding the evolution of species-specific nervous system architecture and function in both male and female genitalia.

• Rice, G., David, J., Kamimura, Y., Masly, J.P., Mcgregor, A., Nagy, O., Noselli, S., Nunes, M.D.S., O'Grady, P., Sánchez-Herrero, E., Siegal, M., Toda, M​., Rebeiz, M., Courtier-Orgogozo, V., Yassin, A. 2019. A Standardized Nomenclature and Atlas of the Male Terminalia of Drosophila melanogaster. Fly 13: 51-64. doi: 10.1080/19336934.2019.1653733.
• Barnard, A.A. and J.P. Masly. 2018. Divergence in female damselfly sensory structures is consistent with a species recognition function but shows no evidence of reproductive character displacement. Ecology and Evolution 8: 12101-12114. doi: 10.1002/ece3.4669.
• Barnard, A.A., O.M. Fincke, M.A. McPeek, and J.P. Masly. 2017. Mechanical and tactile incompatibilities cause reproductive isolation between two young damselfly species. Evolution 71 (10): 2410-2427. doi: 10.1111/evo.13315/full.
• Frazee, S.R. and J.P. Masly. 2015. Multiple sexual selection pressures drive the rapid evolution of complex morphology in a male secondary genital structure. Ecology and Evolution 5 (19): 4437-4450. doi:10.1002/ece3.1721.
• Smith B.N., A.M. Ghazhanfari, R.A. Bohm, W.P. Welch, B. Zhang, and J.P. Masly. 2015. A Flippase-mediated GAL80/GAL4 Intersectional Resource for Dissecting Appendage Development in Drosophila. G3: Genes|Genomes|Genetics 5: 2105-2112. doi:10.1534/g3.115.019810.  PMID: 26276385
• Tanaka, K.M., C. Hopfen, M. Herbert, C. Schlötterer, D.L. Stern, J.P. Masly, A.P. McGregor, and M.D.S.      
• Nunes. 2015. Genetic Architecture and Functional Characterization of Genes Underlying the Rapid
• Diversification of Male External Genitalia Between Drosophila simulans and Drosophila mauritiana. Genetics 200 (1): 357-369. doi:10.1534/genetics.114.174045.  PMID: 25783699
• Masly, J.P. and Y. Kamimura. 2014. Asymmetric mismatch in strain-specific genital morphology causes
• increased harm to Drosophila females. Evolution 68: 2401-2411.  PMID: 24758304
• Cooper, J.T. and J.P. Masly. 2013. Speciation in Diatoms: Patterns, Mechanisms, and Environmental Change. In, Speciation: Natural Processes, Genetics and Biodiversity. Pawel Michalak, ed. Nova Science Publishers, Inc., NY, p. 1-36.
• Masly, J.P. 2012. 170 years of "Lock-and-Key": Genital Morphology and Reproductive Isolation.
• International Journal of Evolutionary Biology 2012: Article ID 247352, 10 pages.  PMID: 22263116
• Masly, J.P., J.E. Dalton, S. Srivastava, L. Chen, and M.N. Arbeitman. 2011. The genetic basis of rapidly
• evolving male genital morphology in Drosophila. Genetics 189 (1): 357-374.  PMID: 21750260