Joan Strassmann

Charles Rebstock Professor of Biology
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  • CB 1137
  • ST. LOUIS, MO 63130-4899
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Professor Strassmann’s work investigates cooperative alliances that have occurred at several important steps in the evolution of life, and have proven evolutionarily and ecologically very successful. Studying how these alliances came to be, how conflicts are subsumed into cooperation, what conflicts remain, and how they influence sociality comprise her dominant research interests.

The evolution of life has resulted in the cooperative aggregation of cohesive units that prosper together. These units may be the same, as with the evolution of multicellularity, or they may be different, as with the evolution of the eukaryote cell. For such cooperation to evolve, conflicts at lower levels must be controlled.

Joan Strassmann studies the evolution of cooperation and the control of conflict in a microbial eukaryote, the social amoeba Dictyostelium discoideum. It is uniquely suitable for this work because transitions that are fixed in most organisms are still flexible. This amoeba preys on bacteria but, when starved, aggregates into a multicellular body that moves towards light, and then differentiates into 20% dead stalk cells that support 80% living spore cells. When the multicellular stage is chimeric, the opportunity for one clone to cheat the other arises.

Strassmann identifies genes involved in this process, look at their rates of evolution using 20 resequenced clones and a handful of sequenced closely related species. She uses experimental evolution to look at the robustness of the social process and the importance of high genetic relatedness within fruiting bodies in maintaining the altruistic caste. She also explores kin recognition and its genetic basis. She studies the evolution of development by constructing pseudo-organisms with artificial life cycles where we manipulate things like single-cell bottlenecks, and has found that some clones carry bacteria with them in a farming and defensive mutualism, and use this to experimentally study mutualism. In sum, her group studies what’s crucial to organismality.

recent courses

Seminars in Ecology and Evolution

What: At least once a week there are seminars from researchers in ecology or evolution. These seminars are given by local people and by visitors. This semester there are also a number of presentations by job candidates. The point of these seminars is to learn about exciting research. What questions are they asking? What are they discovering? What new scientific stories can we hear about ecology or evolution? What makes up these fields anyway? The seminars are often followed by receptions which are a chance to get to know each other better and to ask questions. This course invites undergraduates to listen to these presentations and write about them. After all, this is a major part of the ideas climate at Wash U. It would be a great idea to get in the habit of going to seminars, with this course, or without. In addition to attending seminars, we will meet three times during the semester, early on and a couple of times later. When: Most seminars are 4:00 on Thursdays, though some are on other days. The three meetings will be arranged at a time that works for the students in the course.

    Behavioral Ecology

    This course examines animal behavior from an evolutionary perspective and explores the relationships between animal behavior, ecology, and evolution. Topics include mating systems, sexual selection, parental care, kin selection, and cooperation. There is a strong active - learning component.

      Selected Publications

      See Professor Strassman's complete publications list on her Google Scholar profile.

      Shu, Longfei, Zhang, B., Queller, D. C., Strassmann, J. E. 2018. Burkholderia bacteria use chemotaxis to find social amoeba Dictyostelium discoideum hosts. ISME (International Society for Microbial Ecology) in press.

      Noh, S., Geist, K. S., Tian, X., Strassmann, J. E., Queller, D. C. 2018. Genetic signatures of microbial altruism and cheating in social amoebas in the wild. Proc. Nat. Acad. Sci.

      Inglis, R. F., *Ryu, E., *Asikhia, O., Strassmann, J. E., & Queller, D. C. 2017. Does high relatedness promote cheater-free multicellularity in synthetic life cycles? Journal of Evolutionary Biology, DOI: 10.1111/jeb.13067

      Baldauf, S. L. & Strassmann, J. E. Dictyostelia. 2017. Handbook of the Protists, edited by John M. Archibald, Alastair Simpson and Claudio Slamovits. Springer Press.

      Douglas, T. E. Queller, D. C., & Strassmann, J. E. 2017. Social amoebae mating types do not invest unequally in sexual offspring. Journal of Evolutionary Biology DOI: 10.1111/jeb.13056

      Queller, D. C. & Strassmann, J. E. 2016. Problems of multi-species organisms: endosymbionts to holobionts. Biol Philos 31:855-873. DOI 10.1007/s10539-016-9547-x.

      DiSalvo, S., Haselkorn, T. S., Bashir, U., *Jimenez, D. A., Brock, D. A., Queller, D. C., Strassmann, J. E. 2015. Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria. Proc. Nat. Acad. Sci. USA 112 E5029 – E5037 doi: 10.1073/pnas.1511878112

      Ostrowski, E.A., Shen, Y., Tian, X., Sucgang, R., Jiang, H., Qu, J., Katoh-Kurasawa, M., Brock, D.A., Dinh, C., Lara-Garduno, F., Lee, S.L., Kovar, C.L., Dinh, H.H., Korchina, V., Jackson, L., Patil, S., Han, Y., Chaboub, L., Shaulsky, G., Muzny, D.M., Worley, K.C., Gibbs, R.A., Richards, S., Kuspa, A., Strassmann, J.E., and Queller, D.C.  2015.  Genomic Signatures of Cooperation and Conflict in the Social Amoeba. Current Biology 25: 1661-1665.

      *Levin, S. R., Brock, D. A., Queller, D. C., Strassmann, J. E. 2015. Concurrent co-evolution of intra-organismal cheaters and resisters Journal of Evolutionary Biology DOI: 10.1111/jeb.12618

      smith, j. Queller, D. C., and Strassmann J. E. 2014. Fruiting bodies of the social amoeba Dictyostelium discoideum increase spore transport by Drosophila. BMC Evolutionary Biology 14:105. doi:10.1186/1471-2148-14-105

      Strassmann, J.E. and Queller, D.C.  2014.  Privatization and property in biology.  Animal Behaviour 92: 305 – 311

      Werner. G.D.A, Strassmann, J.E., Ivens, A.B.F. , Engelmoer, D.J.P. , Verbruggen, E., Queller, D.C. , Nöe, R., Johnson, N.C. , Hammerstein, P., E. Kiers, E.T.  2014.  The evolution of microbial markets.  Proc. Natl. Acad. Sci. USA 111:1237-1244.

      Kuzdzal-Fick, J. J., Strassmann, J. E., & Queller, D. C. 2011. High relatedness is necessary and sufficient to maintain multicellularity in Dictyostelium. Science 334: 1548-1550. DOI: 10.1126/science.1213272.

      Strassmann, J. E. & Queller, D. C. 2011. Evolution of cooperation and control of cheating in a social microbe. Proc. Natl. Acad. Sci. USA 108:10855-10862.

      Strassmann, J. E., Gilbert, O. M., & Queller, D. C. 2011. Kin discrimination and cooperation in microbes. Annual Review of Microbiology 65:349-367.

      Brock, D. A., Douglas, T. E.,Queller, D. C., Strassmann, J. E. 2011. Primitive agriculture in a social amoeba. Nature 469:393-396.

      Strassmann, J. E. and Queller, D. C. 2010. The social organism: congresses, parties, committees. Evolution 64:605-616