Queller and Strassmann moved to Washington University from Rice University this summer, bringing a truckload of frozen spores with them.
Although they had worked for years with wasps and stingless bees, Queller and Strassmann's current "lab rat" is the social amoeba Dictyostelium discoideum, known as Dicty for short.
The social amoebae, better known as "slime mold," can be found almost everywhere: in Antarctica, in deserts, in the canopies of tropical forests and in Forest Park, the urban park that adjoins Washington University.
The amoebae spend most of their lives as tiny blobs crawling through soil looking for E. coli and other bacteria to eat.
Things become interesting when bacteria are scarce and the amoebae begin to starve. Then they release chemicals that attract other amoebae, which follow this trail until they bump into one another.
A mound of some 10,000 amoebae forms and elongates into a slug a few millimeters long that crawls forward, but not backward, toward heat and light.
The slug stops moving when it has reached a suitable place for dispersal. Then the front 20 percent of the amoebae die to produce a stalk that the remaining cells flow up to become spores.
The 20 percent of the amoebae in the stalk sacrifice their genes so the other 80 percent can pass theirs on.
When Strassmann and Queller began to work with Dicty, one of the first things they discovered was that the amoebae sometimes cheat.
Scientist Dennis Welker of Utah State University had given them a genetically diverse collection of wild-caught clones--genetically identical amoebae.
They mixed amoebae from two clones together, then examined the fruiting bodies to see where the clones ended up.
Each fruiting body included cells from both clones, but some clones c
|Contact: Cheryl Dybas|
National Science Foundation