Figure 1. .

Detection of mtDNA-deletion mutations by major arc mtDNA-genome amplification. Total DNA from microdissected COX⁻/SDH⁺⁺ fibers was subjected to long-extension PCR. mtDNA-specific primers (F4840–R766) that amplify ∼13 kb of the full-length genome, including two origins of replication, were used. Full-length amplification products were detected in ETS-normal fibers (n). Smaller amplification products were identified in ETS-abnormal fibers (8, 11, 28, 31, and 34). Amplification of total mtDNA from tissue homogenates (T) detected both full-length and smaller amplification products. M = DNA molecular-weight standards.