Fig. 1

Overview of the addax MHC physical map construction. a BAC library construction. Fibroblasts were embedded into low-melting point agarose to form plugs for subsequent genomic DNA isolation. Genomic DNA fragments of 100–300 Kb were ligated into the pCC1BAC vector. White colonies were picked into 384-well plates after transformation. b 3D-PCR screening strategy. To improve screening efficiency, the entire addax BAC library composed of 500,384-well plates was divided into 50 super-pools. After the positive MHC clones were determined in a certain super-pool by the first dimension of PCR, the second dimension of PCR was further performed on 10 plates. Then, the third dimension of PCR screening was continued on 16 rows and 24 columns. The intersection of a row and column indicated a potential positive clone covering the addax MHC region. c The physical map covering the addax MHC region was assembled by integrating the results from sequence-specific PCR and DNA fingerprinting