Constitutive amplification of a zinc finger protein gene in cattle

The human OZF gene encodes a protein consisting essentially of zinc finger motifs of the Krüppel type. Evolutionary studies revealed amplification of the bovine OZF gene in cattle. Domestic cattle includes two major subspecies: taurine (Bos primigenius taurus) and zebu (B. p. indicus). Amplified sequences were found in both subspecies and mapped to the same locus of chromosome X in band q11. No amplification was found in other bovids and in particular in Bison, the closest related genus to the genus Bos. One copy of the amplified locus was cloned and sequenced. It encodes a protein sharing 95% identity with the human OZF protein. The bovine OZF gene was detected in an additional locus on chromosome 18 in both Bos and Bison, in band q23-24, which is likely to represent the ancestral position of the OZF gene. This is the first evidence of gene amplification in a mammalian species during evolution.