Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2006
Publication Date: 5/1/2007
Citation: Palti, Y., Rodriguez, F., Gahr, S.A., Hansen, J.D. 2007. Evolutionary history of the abcb2 genomic region in teleosts. Developmental and Comparative Immunology 31(5):483-498. Interpretive Summary: The U.S. salmonid aquaculture industry suffers severe economic loss to diseases. Every year, viral epidemics in farmed Atlantic salmon and rainbow trout have resulted in production losses of greater than 90% accounting for millions of dollars of lost revenue. The major histocompatibility complex (MHC) is known as the gateway to immune responses and is involved in both adaptive and innate immunity. Efforts to use molecular technologies in the genetic improvement of agricultural species have recently included the genetic mapping of rainbow trout. Detailed mapping and gene annotation of the MHC in rainbow trout and the development of genetic markers for the different major histocompatibility (MH) regions will provide useful tools for genetic improvement of disease resistance in rainbow trout and other salmonids.
Technical Abstract: Gene duplication, silencing and translocation have all been implicated in shaping the unique genomic architecture of the teleost MH regions. Previously, we demonstrated that trout possess 5 unlinked regions encoding MH genes. One of these regions harbors ABCB2 which in all other vertebrates classes is found in the MHC class II region. In this study, we sequenced a BAC contig for the trout ABCB2 region. Analysis of this region revealed the presence of genes homologous to those located in the human class II (ABCB2, BRD2, yDAA), extended class II (RGL2, PHF1, SYGP1) and class III (PBX2, Notch-L) regions. The organizatin and syntenic relationships of this region were then compared to similar regions in humans, Tetraodon and zebrafish to learn more about the evolutionary history of this region. Our analysis indicates that this region was generated during the teleost-specific duplication event while also providing insight about potential MH paralogous regions in teleosts.