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Title: PHYSICAL AND GENETIC MAPPING OF RAINBOW TROUT MAJOR HISTOCOMPATIBILITY REGIONS: EVIDENCE FOR DUPLICATION OF THE CLASS I REGION

Author
item PHILLIPS, RUTH - WASHINGTON STATE U
item Palti, Yniv
item HANSEN, JOHN - U OF MARYLAND

Submitted to: Immunogenetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2003
Publication Date: 11/1/2003
Citation: Phillips, R., Palti, Y., Hansen, J. 2003. Physical and genetic mapping of rainbow trout major histocompatibility regions: evidence for duplication of the class I region. Immunogenetics. 55(8):561-569.

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 of the MHC in rainbow trout and the development of genetic markers for the different MH regions will provide useful tools for genetic improvement of disease resistance in rainbow trout. This report gives details on the development of new MHC markers and the mapping of 4 MH regions in rainbow trout.

Technical Abstract: Previous segregation analysis in trout suggested that the class I and II regions reside on completely different chromosomes. To learn more about MHC genomics in trout, we have isolated BAC clones harboring class IA and IB loci, a single BAC clone containing an MH class II gene (DAB) as well as BAC clones containing the ABCB2 gene. Upon PCR and sequence confirmation, BAC clones were labeled and used as probes for in situ hybridization on rainbow trout metaphase chromosomes for determination of the physical locations of the trout MH regions. Finally, SNPs, RFLPs and micro-satellites found within the BAC clones allowed for these regions to be assigned to specific linkage groups on the OSUxHotcreek and OSUxArlee genetic linkage maps. Our data demonstrates that the trout MH regions are located on at least four different chromosomes and the corresponding linkage groups while also providing direct evidence for the partial duplication of the MH class I region in trout.