Fig. 2: Magnitude of intrasarcomere cross-sectional area heterogeneity is related to mitochondrial location.

a–k 3D rendering of representative mitochondrial network structures from eleven muscle types from mouse, Drosophila, and human tissues showing Z-adjacent regions (light blue) and A-adjacent regions (red). l Strong linear correlation (black dotted line, linear regression, p < 0.001) between Z-adjacent mitochondrial abundance and sarcomere cross-sectional area (CSA) heterogeneity. Individual points represent individual muscle cell values. m Weak linear correlation (black dotted line, linear regression, p = 0.024) between mitochondrial content and sarcomere CSA heterogeneity. n Lack of correlation between individual mitochondrial volume and sarcomere CSA heterogeneity. o Simulations of simple sarcomere geometry models showing proportional reduction in isometric force when entire sarcomere CSA is reduced and minor reduction in force when only the Z-disk CSA is reduced.