Location and expression of genes surrounding the identified QTL in chromosomal region 6p21.32-33. Top: Schematic of chromosomal region 6p21.32-33 from the NCBI Gene website depicting annotated genes surrounding the identified QTL (red arrow). Bottom: Total RNA was purified from cultured primary HCE and TM-1 cells and used for cDNA synthesis. Reverse transcription-PCR using cDNA was performed using gene-specific primers from MUC21, MUC22, and HCG22, and the products were resolved on a 1.5% agarose gel. Primers for HCG22 were designed to detect only the coding transcript. Similar results were obtained using three primary TBM cell lines (not shown). RTase, reverse transcriptase; HCE, primary corneal epithelial cells obtained from corneal rims.