Analysis of large tandem array in 8q21.2. A) Information from the UCSC genome browser (hg18) showing region containing the 12 kb tandem repeat from 8q21.2. This repeat array contains an "87 kb" gap with ~5 repeat units on the proximal side and ~1.5 repeats on the distal side. The repeats can be seen in the repeating patterns of the Repeat Masker Tracks. The AF495523 (Gor1) gene is found once in each repeat unit. Copy number variation was detected at this repeat array using both BAC microarrays and fosmids. The restriction enzyme PmeI does not cut in the 12 kb repeats, but cuts close to the edge of the array in the genomic DNA sequence. The position of the PCR amplified probes used on the Southern blot are indicated. B) Pulsed Field Gel analysis of the array size in two pedigrees (lanes 1–4, and lanes 5–10).