Figure 4. Probability that a feature is conserved as a function of sample size.

The observation that squid HMM is relatively compact in the off state, together with this same observation in each of the other myosins previously examined (see text), increases the probability that this conformation is conserved in myosin-linked regulation. The formula for probability (P), shown on the y-axis, as a function of the size of a sample for which all members share the conformational feature, was developed by Ji Li (see Methods). Shaded region reflects the approximate number of independent species for which the compact conformation of off-state myosin has been observed (see text).