Fig. 5. Principal components analysis for microtubule sliding pattern data. The first principal component (PC1) explained 70.9% of the variation among microtubule sliding patterns for axonemes isolated from wild-type and mutant strains in both low and high Ca²⁺ buffer. Larger PC1 values have higher frequencies of sliding patterns P7 and P8 and lower frequencies of patterns P3-P6. The second principal component, PC2, explained 13.9% of the variation; larger values of PC2 have higher frequencies of sliding pattern P6 and lower frequencies of sliding pattern P4.