Fig. 6. Principal components analysis for data derived from the analysis of doublet number present on the dynein exposed edge of the active area. The first principal component (PC1) explained 69.5% of the variation; larger values for PC1 had higher frequencies of Db2 and lower frequencies of Db3 on the dynein exposed edge of the active area. The second principal component (PC2) explained 18.6% of the variation, with larger values for PC2 having larger frequencies of Db1 and lower frequencies of Db3 on the dynein exposed edge.