Spatial gene expression comparison of muscle cell using the VMus3D of myoblast-myotube transition and skeletal muscle specificity index. Skeletal Muscle Specificity: computed from the difference between the normalised mean expression in skeletal muscle and the median expression in the remaining tissues surveyed. Some differentially expressed components of the myofibril have not been labelled for display simplicity (Troponins and Tropomyosin). Colours are coded according to log ratio thresholds. Yellow: less than or equal to two, purple greater than two but less than equal to five and blue greater than five. Grey indicates no data.