Fig. 2: Fiber typing in cloned wildtype (WT) porcine embryos.

a–c Immunohistochemical staining of cross sections of hindlimb from WT embryos. Fast-twitch fibers were detected using myosin heavy chain fast (yellow) and slow-twitch fibers were stained with myosin heavy chain slow (red). Nuclei were labeled with DAPI (blue). Across gestational stages, E41 (a), E62 (b), and E90 (c), representative sections with fast-twitch fibers, slow-twitch fibers, and merged images are displayed vertically. Scale bar, 100 µm. d Quantification of distribution of slow and fast-twitch fibers in E90 embryos are depicted (n = 4). Bar graphs represent mean ± s.e.m. with statistical validation using unpaired student’s t-test (***p < 0.001). e–g Immunohistochemical staining of hindlimb section with nuclei (blue), laminin (green), and embryonic myosin heavy chain (eMyHC, red). Across gestational stages E41 (e), E62 (f), and E90 (g), representative sections with laminin, embryonic MyHC and merged image are displayed vertically. Scale bar, 100 µm. h, i Quantitative analysis of muscle fiber cross-sectional area at each developmental stage (n = 3–5 each stage). The summarized cross-sectional area of muscle fibers (µm²) at each developmental stage is depicted in (h), and the distribution of muscle fiber cross-sectional areas, ranging from 10 to 400 µm², segmented into intervals of 50 µm² is presented in (i). Bar graphs represent mean ± s.e.m. with statistical validation using one-way ANOVA and Tukey’s test for average cross-sectional area within muscles (h).