The Analysis of Bovine Olfactoroy Receptor (OR) Subgenome Supports the Biological Importance of the OR System in Artiodactyla

Mammalian olfactory receptors (ORs) are encoded by the largest multigene family in the genomes of mammals. We report here the result of a whole genome scanning of OR genes in the cattle genome. For the identification of OR genes, we identified sequences with OR specific motifs and their variants residing at transmembranes 3, 6 and 7 from cattle genome assembly build UMD 3.1. The cattle genome contains 1071 OR related sequences including 881 functional, 190 pseudo and 332 partial OR genes. The OR genes were located in 49 clusters on 29 cow chromosomes. We classified them into 18 families consisting of 3 class I and 15 class II families. Among the OR genes, 72 were specific for cattle. Cattle is the second species with their OR subgenome analyzed in the artiodactyla and our results support the importance of the OR system for the survival of artiodactyla.