Fig. 4. MHC isoform expression in bundles of fibres from rectus lateralis (7Rl) and from retractor bulbi (7Rb, 10Rb) and in two larger samples of retractor bulbi muscle (Rb). The same MHC isoforms were detected by RT-PCR (A) and SDS-PAGE (B). Two samples of Rb are shown because it is not possible to detect all six bands in the same sample due to the different proportion of each isoform and to the distribution of the isoforms inside the muscle. S, size standards.