Localization of BRRN1, the human homologue of Drosophila barr, to 2q11.2.

cDNA probe confirmed that BRRN1 maps to chromosome 2 Localization of BRRN1, the Human (Fig. 1A) (14). To identify BRRN1-containing YAC clones we screened the Homologue of Drosophila barr, CEPH-Mark II YAC library by PCR. We used two oligonucleoto 2q11.2 tide primer pairs designed to yield PCR products corresponding to positions 448–625 (primer set I) and 2229–2402 Olga A. Cabello,* Antonio Baldini,* Manzoor Bhat,† (primer set II) in the BRRN1 cDNA. Both sets of primers Hugo Bellen,*‡ and John W. Belmont*§ yielded unique PCR amplification products on human genomic DNA template. Seven of the PCR-positive clones also exhibited BRRN1 hybridization on Southern analysis. Clone *Department of Molecular and Human Genetics, †Howard Hughes Medical Institute, ‡Department of Cell Biology, and §Departments of 539D8 encompassed all restriction fragments identified by Microbiology & Immunology and Pediatrics, Baylor College of Medicine, the genomic Southern blots (Fig. 1A). Alu-PCR products of Houston, Texas 77030 YAC 539D8 were prepared as previously described (1) and used as probes for FISH, yielding a discrete hybridization