Argininosuccinate synthetase pseudogene 1 (ASSP1), interferon-beta 3 (IFNB3) gene, and diazepam binding inhibitor (DBI) gene have previously been mapped to human chromosome 2. Their nucleotide sequences, recorded in the GENBANK data base, were used to generate DNA primers to amplify specific sequences using the polymerase chain reaction (PCR). These primers failed to amplify DNA sequences when used to analyze microcell hybrid clones containing human chromosome 2. In order to map these genes, a panel of somatic cell hybrids was analyzed by PCR with these primer sets. The results of these experiments place ASSP1 sequences on human chromosome 6, IFNB3 on human chromosome 8, and DBI on human chromosome 6.