Figure 31.

Three main approaches currently used to identify and sort molecular heterogeneity. The first approach (left panel) is based on statistical analysis of 2D images (a priori analysis) to detect the heterogeneity of the sample in its images. The initial sorting is done prior to any 3D reconstruction. The second approach (middle panel) requires an initial 3D map to separate the images into subsets according to their orientation. Analysis of structural heterogeneity is done in 2D for each orientation subset. The third method (a posteriori analysis) is based on examination of variations in multiple 3D maps (right panel). Reproduced with permission from ref (220). Copyright 2010 Elsevier Inc.