The human chromosome 3 locus coding for hepatocyte growth factor-like protein/macrophage stimulating protein (HGFL/MSP) is homologous to two sets of amplified loci on human chromosome 1 at 1p36. One copy of one of the amplified loci (D1F15S1A) has been further characterized by restriction enzyme and DNA sequence analysis. A total of 8331 bp of continuous sequence was determined for this locus. The first 6878 bp of sequence is 96.1% identical to the HGFL/MSP gene, while there is no homology between the two genes following nucleotide 6878. Based on the presence of a 5 bp deletion in putative exon 2 and several downstream stop codons it is very likely that this gene is a pseudogene. Screening of a human liver cDNA library with a chromosome 1-specific probe indicates that at least several other members of the chromosome 1 loci are transcribed.