Gene copy number in AAV-injected muscle tissue. (A) Southern blot analysis of genomic DNA extracted from murine skeletal muscle injected with AAV vectors. The first 3 lanes are from mice injected with AAV-1–F.IX at the doses listed beneath each lane; the next 3 lanes are from mice injected with AAV-2–F.IX. Copy number standards were prepared by adding 10, 100, or 1000 pg plasmid to 20 μg murine genomic DNA.