Everyone wins (Image: Thomas Deerinick, NCMIR/SPL)

TUG of war could well be the oldest game in the world. Cells use it for division, and now researchers have measured the forces involved when an amoeba plays the game.

Hirokazu Tanimoto and Masaki Sano at the University of Tokyo, Japan, studied what happens during the division of Dictyostelium – a slime mould that has barely changed through eons of evolution. The amoeba uses tiny projections or “feet” to gain traction on a surface.

The pair placed the amoeba on a flexible surface embedded with fluorescent beads. They used traction force microscopy to measure how the organism deformed the pattern of beads: the greater the deformation, the greater the force.


Dictyostelium normally exerts a force of about 10 nanonewtons when it moves, but the pair found this roughly doubles during division. That’s because the cell uses its feet to pull itself in opposite directions, as if playing tug of war with itself.

The forces involved are about 100 billion times smaller than those used in the human form of the game, Tanimoto says (Physical Review Letters, in press).