Example of an oscillatory motion of a droplet around the oocyte center. (A) Images in transmitted light of a droplet centered in prophase I. One image is shown every 140 min. Scale bar is 10 µm. The yellow arrow points at the oil droplet. (B) Distance of the droplet centroid to the oocyte center as a function of time (in minutes) from the images shown in A. Two oscillations of the droplet can be observed at 200 min and at 600 min. It is worth noting that the droplet encounters the nucleus when it reaches the center. (C) Distribution of diameter lengths for all droplets that are not central at the beginning of the experiment (n = 29 oocytes); four independent experiments. (D) MSD of oil droplets as a function of the delay (in seconds) on a log/log scale. n = 29 oocytes in prophase I (black curve), and n = 14 oocytes in prophase I + Cyto D (blue curve); three independent experiments. The dotted gray line represents a linear regression with a slope of 1. (E) Results obtained from the fitting of the MSD curve from D on a log-log scale. α represents the slope of the curve. The fit is done on the first 100 points of the curve. (F) Evaluation of the diffusion coefficient from the fit of the MSD curve from D. The fit is done on the first 100 points of the curve. The diffusion coefficient is then evaluated considering the following formula: MSD = 4.D.t (with t as the delay).