Genomic map of the bovine Type I IFN locus. Blast searches of the bovine genome database revealed that all matches to known IFN genes, except IFNK, reside within two sub-loci, illustrated in the gene map shown in Fig. 2. Both the position of each gene relative to the line and the direction of the arrow on the map denote the direction of transcription. The subfamily for each gene is designated by the final letter of the abbreviated name. Pseudogenes are indicated by a box instead of an arrow and the letter "p" after the subfamily designation. Specific gene clusters have been labeled according to the subfamily or subfamilies they contain. A recent example of gene duplication is illustrated in the IFNW/IFNA cluster 1 and 2. The bracketed gene set in IFNA/IFNW cluster 1 is a palindrome to the bracketed gene set in the IFNA/IFNW cluster 2 with identical coding sequences for genes specified by correspondingly colored boxes.