Queller

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.

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.