CNVs within olfactory receptor (OR) clusters. NCBI map viewer http://www.ncbi.nlm.nih.gov/projects/mapview/map_search.cgi?taxid=9913 was searched for the string "olfactory receptor" and the output was the base for the presented genome view of OR locations (red boxes). For each chromosome, the number of database hits (red font), including all types of redundant map elements, was indicated under the corresponding chromosome number (underlined blue font). Common OR copy losses and gains detected in this study are indicated with red and blue arrowheads, respectively. Circles around OR clusters indicate CNVRs (frequency > 2.5%) which have been previously observed in cattle autosomes.