The Haag Lab

Evolution of Reproduction

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A Tribute to Rudolf Raff



Department of Biology

University of Maryland, College Park


Eric's Office:  Biology/Psychology Building Room 0256 

Telephone: (301) 405-8534


Lab:  Biology/Psychology Building Room 0245

Telephone: (301) 405-8625

UMD Devo Club Schedule


Research Interests

       The Haag laboratory studies variation in animal reproductive mode, which evolves quickly yet has tremendous organismal significance. We explore both the developmental novelties required to allow a new strategy to emerge, and also the various consequences of adopting it.  Currently we focus on the evolution of self-fertile hermaphroditism using the model nematode Caenorhabditis elegans.

       A long-standing project seeks to identify molecular and genetic mechanisms that allowed selfing hermaphrodites to produce sperm in a female body. Independently evolved hermaphrodites also provide interesting case studies in convergent evolution.  The genomic and reproductive responses to self-fertility is a newer area of research.

Work in the lab currently includes the following projects: 

  • classical and reverse genetic analysis of sex determination in multiple Caenorhabditis species
  • evolutionary dynamics of germline RNA-binding proteins
  • basic and comparative characterization of key proteins of the nematode sex determination pathway
  • genome-level consequences of mating system evolution in Caenorhabditis species
  • the impact of selfing on sperm function and sperm competition
  • interspecies hybrid genetics                      


A "flower" of C. briggsae, composed (from outside) of adult hermaphrodites, adult males, and L2 larvae expressing a myo-2::GFP pharyngeal marker, which indicates presence of a transgene bearing two C. nigoni mss paralogs. The center is an immunofluorescence image of sperm stained for the MSS surface protein, which impacts sex ratio in selfing species (see Yin et al. 2018).  Images and montage by Da Yin.

Feel free to contact Eric if you are interested in participating in this work. 

* For UMD undergraduates, please see this page for how to apply.

* For prospective graduate students and postdoctoral researchers, please see this page.

Recent Publications (since 2010):

Koboldt, DC, Staisch, J, Thillainathan, B, Haines, K, Baird, SE, Chamberlin, HM, Haag, ES, Miller, RD, and Gupta, BP (2010) A toolkit for rapid gene mapping in the nematode Caenorhabditis briggsae. BMC Genomics 11: 236. PDF

Woodruff, G.C., Eke, O., Baird, S.E., Félix, M.A., and Haag, E.S. (2010). Insights into species divergence and the evolution of hermaphroditism from fertile interspecies hybrids of Caenorhabditis nematodes. Genetics 186: 997-1012. PDF

Ross, J.A., Koboldt, D.C., Staisch, J.E., Chamberlin, H.M., Gupta, B.P., Miller, R.D., Baird, S.E., and Haag, E.S. (2011). Caenorhabditis briggsae recombinant inbred line genotypes reveal inter-strain incompatibilities and the evolution of recombination. PLoS Genetics  7: e1002174 PDF

Haag, E.S. and Lenski, R.E. (2011) L’enfant terrible at 30:  the maturation of evolutionary developmental biology.  Development  138: 2633-38. PDF

Beadell, A.V., Liu, Q., Johnson, D.M., and Haag, E.S. (2011) Independent recruitments of a translational regulator in the evolution of self-fertile nematodes.  Proc. Natl. Acad. Sci USA 108: 19672-27 PDF

Liu, Q., Stumpf, C., Thomas, C.G., Wickens, M., and Haag E.S. (2012) Context-dependent function of a conserved translational regulatory module.  Development 139: 1509-21.PDF

Thomas, C.G., Woodruff, G.C., and Haag, E.S. (2012) Causes and consequences of the evolution of reproductive mode in Caenorhabditis nematodes. Trends in Genetics 28: 213-220. PDF

Thomas, C.G., Li, R., Smith, H.E., Woodruff, G.C., Oliver, B., and Haag, E.S. (2012).  Simplification and desexualization of gene expression in self-fertile nematodes. Current Biology 22: 2167-2172. PDF   Supp. Mats

Liu, Q. and Haag, E.S. (2014). Evolutionarily dynamic roles of a PUF RNA-binding protein in the somatic development of Caenorhabditis briggsae. Journal of Experimental Zoology, Part B 322:129-141 PDF

Cbr-puf-2 confocal

Ting, J.J., Woodruff, G.C., Leung, G., Shin, N-R, Cutter, A.D., and Haag, E.S. (2014). Intense sperm-mediated sexual conflict promotes reproductive isolation in Caenorhabditis nematodes. PLoS Biology 12: e1001915.

rogue sperm

Woodruff, G.C., Knauss, C.M., Maugel, T.K., and Haag, E.S. (2014). Mating damages the cuticle of C. elegans hermaphrodites. PLoS ONE 9: e104456.

Beadell, A.V. and Haag, E.S. (2015) Evolutionary Dynamics of GLD-1-mRNA complexes in Caenorhabditis nematodes.
Genome Biology & Evolution 7: 314-335.

Thomas, C.G. and Haag, E.S. (2015) Fundamentals of Comparative Genome Analysis in Caenorhabditis Nematodes. Methods in Molecular Biology 1327: 11-21

Yin, D., Schwarz, E.M., Thomas, C.G., Felde, R.L. , Korf, I.F., Cutter, A.D., Schartner, C.M., Ralston, E.J., Meyer, B.J., and Haag, E.S. (2018). Rapid genome shrinkage in a self-fertile nematode reveals sperm competition proteins. Science 359: 55-61


Haag, E.S., Fitch, D.H.A., and Delattre, M. (2018) From "the Worm" to "the Worms" and back again: The Evolutionary developmental biology of nematodes. Genetics 210: 397-433

Hu, S, Skelly, L.E., Kaymak, E., Freeberg, L., Lo, T-W., Kuersten, S., Ryder, S.P., and Haag, E.S. (2019) Multi-modal Regulation of C. elegans hermaphrodite spermatogenesis by the GLD-1-FOG-2 complex. Developmental Biology 446: 193-205.

Yin, D. and Haag, E.S. (2019) Evolution of sex ratio through gene loss. Proc. Natl. Acad. Sci. USA 116: 12919–12924.

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Research in the Haag Lab has been supported by grants from NIGMS and NSF

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