Bone morphogenetic protein 2A (BMP2A), a member of the decapentaplegic-Vg-related family, belongs to the transforming growth factor beta superfamily and has a striking sequence similarity to the decapentaplegic locus in Drosophila melanogaster, a major determinant of pattern specification during embryogenesis. BMP2A is thought to be involved in cartilage and bone formation during embryogenesis, but may have additional functions in morphogenesis as implied by its expression in various organs and embryonic tissues of mice. Human BMP2A, assigned to chromosome 20 by the use of human-Chinese hamster ovary cell hybrids, is considered to be a reasonable candidate gene for the autosomal dominant disease of fibrodysplasia (myositis) ossificans progressiva. We have confirmed the localization of BMP2A to chromosome 20 and regionally assigned the locus to 20p12 by radioactive and nonradioactive in situ hybridization.