The region on SSC 7 (74 Mb) harbors the T-cell receptor alpha locus (TCRA), interferon-stimulated transcription factor 3 gamma (IRF9), and ribonuclease RNase A family 4 (ANG) genes, which have previously been associated with APP natural infection (Skovgaard et al., 2010). The gene discussed is IRF9; the disease is infection.