Angus dwarfism has been localized to bovine chromosome 6 (BTA6) by linkage mapping. Four positional candidate genes suspected to alter bone development have been identified and are under analysis. A causative mutation was found in the PRKG2 gene. Subsequently, a genetic test was developed so that Angus breeders may select against dwarfism. This test successfully predicted which calves were dwarves with 100% accuracy in a breeding experiment recently concluded at Iowa State. Preliminary data in cell culture indicates that the mutation discovered changes the function of the PRKG2 gene, strongly suggesting it is the causative mutation in American Angus.