Somatic cell parasitism and the evolution of somatic tissue compatibility.

Abstract

Selection pressures proposed to account for the convergent evolution of self/not-self recognition systems in lower organisms include defense against microbial parasites and somatic cell variants. Direct support for the existence of somatic cell parasites in natural populations has been lacking. The occurrence of a somatic cell parasite in the cellular slime mold Dictyostelium mucoroides is reported and the implications of this phenomenon to the evolution of mechanisms of somatic tissue compatibility are discussed.