Amino acid sequences of two tryptic peptides derived from enriched bovine osteogenic protein preparations revealed considerable homology to two members of the TGF-beta (transforming growth factor beta) supergene family, DPP (decapentaplegic protein) of Drosophila and Vg-1 (vegetal protein) of Xenopus. Building upon this information we constructed a synthetic consensus gene to use as a probe to screen human genomic libraries. This resulted in the isolation of three interrelated genes. Among these were BMP-2b and BMP-3 which have recently been described by others. The third gene, termed OP-1 (osteogenic protein one), is new and was subsequently shown to encode the human homolog of a major component of bovine osteogenic protein. The genomic clones were used to isolate the corresponding complementary DNA (cDNA) clones. Sequence analysis indicates that OP-1 is a relative of the murine Vgr-1 (Vg-1 related gene). This report describes the cDNA structure and putative amino acid sequence of OP-1.