Correlation between the nebulin super-repeats and Z-repeats in the 53 analyzed species. There is a weak but significant correlation (slope is significantly different from 0, P = 0.001). Thus, as the number of super-repeats increases, there is a tendency for the number of Z-repeats to increase as well (note that all 53 species were analyzed, but that several of their data points overlap. When analyzing the individual groups separately, fish, mammals, and primates had Z-repeat-versus-super-repeat correlations that were significant).