Before revision:  At the cortex, to relate dynein residency and forces generating, we tracked dynein and found two dynamically distinct populations. One of them would correspond to force generating events. Our experiments also indicated that an asymmetric (polarized) dynein-microbutule on-rate, causes the force imbalance positioning the spindle.
After revision:  At the cortex, dynein tracks can be classified as having either directed or diffusive-like motion. Diffusive-like tracks reveal force-generating dyneins. Their densities are higher on the posterior tip of the embryos, where \text{GPR-1/2 the force imbalance positioning the spindle.