Joan Strassmann

Using new gene sequencing techniques, Washington University biologists are taking a closer look at the behavior of the social amoeba Dictyostelium discoideum, or Dicty for short.

Joan E. Strassmann is a member of the National Academy of Sciences and the Charles Rebstock Professor of Biology in Arts & Sciences at Washington University in St. Louis, where she studies the evolution of conflict and cooperation. She writes a popular blog on becoming a biology professor with the goal of diversifying the professoriate. […]

The social amoeba Dictyostelium discoideum can farm symbiotic bacteria for food by carrying them from generation to generation. New research shows that these bacteria can also protect the amoeba from environmental toxins.

Genes inherited from mothers (matrigenes) and fathers (patrigenes) usually work harmoniously in the offspring. However, kin selection theory predicts these genes may be in conflict in interactions among relatives in which they are unequally represented (half-siblings). In honey bees, patrigenes are predicted to favor daughters that lay eggs themselves rather than remaining sterile and rearing their half-sisters’ offspring. An experimental test bears out this prediction.

A  bacterial infection turns non-farming social amoebae into farmers, Washington University evolutionary biologists report in the Aug. 24 issue of Proceedings of the National Academy of Sciences.

What is it with cheating? Cheaters seem to have an immediate advantage over cooperators, but do they have an evolutionary advantage? A study published in Current Biology suggests the benefits of cheating change with its prevalence,in a population. Cheaters may succeed, for example, only when they are rare, and fail when they become so numerous they push out cooperators.

Biology researchers at Washington University in St. Louis are placing their bets on the wild side as they prepare a pack of social amoeba for competition Friday, May 16, in the first-ever Dicty World Race, an international science competition that carries a $5,000 prize for the single-celled organism deemed to be the “smartest and fastest” in negotiating a microscopic maze.

Biologist Joan E. Strassmann, PhD, was installed Jan. 23 as the Charles Rebstock Professor of Biology in Arts & Sciences in a ceremony in Holmes Lounge. Following the formal installation, Strassmann gave an entertaining talk about a high-stakes gamble she and Queller made 15 years ago: to switch from studying cooperation and conflict in social insects, famous for their complex societal arrangements, to studying it in an amoeba, whose claim to fame had been its simple lifestyle.

Microbes set up their own markets, comparing bids for commodities, hoarding to obtain a better price, and generally behaving in ways more commonly associated with Wall Street than the microscopic world. This has led an international team of scientists, including two from Washington University in St. Louis, to ask which, if any, market features are specific to cognitive agents.

Evolutionary biologist W.D. Hamilton predicted that organisms ought to evolve the ability to discriminate degrees of kinship so as to refine their ability to direct help to individuals with whom they shared the most genes. But two WUSTL biologists point out that there seem to be many cases where “a veil of ignorance” prevents organisms from gaining this kind of information, forcing them to consider a situation from the perspective of all members of their group instead of solely from their own perspective or that of their close kin.

Three Washington University in St. Louis scientists are among the 84 members and 21 foreign associates elected to the National Academy of Sciences this year. Election to the academy is considered one of the highest honors that can be accorded a U.S. scientist or engineer.

This fall Joan Strassmann, PhD, professor of biology in Arts & Sciences taught a course in behavior ecology that was also an official Wikipedia course that required students both to edit an existing Wikipedia entry and then either add 25 references and 2500 words to a second entries or to create new ones. “No work by students as good as Washington University’s students should ever end up in a professor’s drawer,” said Strassmann. “It was their responsibility as smart people who were getting a great education to help others.”

We would all like to believe that there is a kind of karma in life that guarantees those who cheat eventually pay for their bad behavior, if not immediately, then somewhere down the line. But a study of a new gene in the amoeba Dictyostelium discoideum suggests that, at least for amoebae, it is possible to cheat and get away with it.

Any multicellular animal poses a special difficulty for the theory of evolution. Most of its cells will die without reproducing, and only a privileged few will pass their genes. Given the incentive for cheating, how is cooperation among the cells enforced? In the Dec. 16 issue of the journal Science, Washington University in St. Louis biologists Joan Strassmann and David Queller suggest the answer is frequent population bottlenecks that restart populations from a single cell.