Some social amoebae farm the bacteria they eat. Now a collaboration of scientists at Washington University in St. Louis and Harvard University has taken a closer look at one lineage, or clone, of D. discoideum farmer. This farmer carries not one but two strains of bacteria. One strain is the “seed corn” for a crop of edible bacteria, and the other strain is a weapon that produces defensive chemicals. The edible bacteria, the scientists found, evolved from the toxic one.
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.