Fig. 3.

Z-score histogram of the 120 main normal MAs, with the y-axis (number of probes) being rescaled as the z-score increases and the number decreases. The blue line is the mean of the number of probes, and the red lines are the means ± SD. As expected, most of the probes (69%) have negative z-scores, indicating that many of these are essentially “off” or of very low expression for muscle tissue. Only 5.9% had a z-score value above 1.0, only 2.4% above 2.0, and only 0.6% above 5.0.