Dr. Johanna Kowalko

Adjunct Assistant Professor
Johanna Kowalko

Dr. Kowalko received her B.A. in Biology from Brown University in 2005.  In 2013 she received her Ph.D. from Harvard University, where her mentor was Dr. Cliff Tabin. In fall 2013, she joined GDCB as an Assistant Scientist and Lecturer.


I am interested in understanding the genetic basis of behavioral variation in natural populations.  I study behavior in two systems, the zebrafish, Danio rerio, as a model system for understanding the genetic basis of behavior, and the cavefish, Astyanax mexicanus, to study the evolution of behavior.  Astyanax mexicanus exists in two forms, a river-dwelling surface form and multiple, independently-evolved blind cave forms.  Surface and cavefish differ in a number of morphological and behavioral traits, but are interfertile, and can be bred together for genetic mapping of traits, making them an excellent system for the study of the genetic underpinnings of behavioral evolution.


Biol 101


  • Rohner, N., Jarosz, D. F., Taipale, M., Kowalko, J., Yoshizawa, M., Jeffery, W. R., Borowsky, R. L., Lindquist, S., and C. J. Tabin.  (2013). Cryptic variation in morphological evolution: HSP90 as a capacitor for the adaptive loss of eyes in cavefish. Science (In press).
  • Kowalko, J. E., Rohner, N., Rompani, S. B., Peterson, B. K., Linden, T. A., Yoshizawa, M., Kay, E. H., Weber, J., Hoekstra, H. E., Jeffery, W. R., Borowsky, R., Tabin, C. J. (2013). Loss of schooling behavior in cavefish through sight-dependent and sight-independent mechanisms.  Curr. Biol. 23 (19): 1874-83.
  • Kowalko, J. E., Rohner, N., Linden, T. A., Rompani, S. B., Warren, W. C, Borowsky, R., Tabin C. J., Jeffery, W. R., and M. Yoshizawa.  (2013). Convergence in feeding posture occurs through different genetic loci in independently evolved cave populations of Astyanax mexicanus.  Proc. Natl. Acad. Sci. USA 110 (42) 16933-16938.
  • Kowalko, J. E. and Sebert, M. E. (2008).  The Streptococcus pneumonia competence regulatory system influences respiratory tract colonization.  Infect. Immun. 76 (7): 3131-40.
Area of Expertise: 
Genetic basis of behavioral variation in natural populations using zebra and cave fish model systems
B.A., Biology, Brown University, 2005
Ph.D., Harvard University, 2013
640 Science ll