Exogenous lipid vesicles induce endocytosis-mediated cellular aggregation in a close unicellular relative of animals.

is a protozoan that may both reveal aspects of animal evolution and also curtail the spread of schistosomiasis, a neglected tropical disease. exhibits a chemically regulated aggregative behavior that resembles cellular aggregation in some animals. This behavior may have played a key role in the evolution of animal multicellularity.