Single nucleotide polymorphisms (SNPs) in immune response genes have been reported as markers for susceptibility to infectious diseases in human and livestock.A disease caused by cyprinid herpesvirus 3 (CyHV-3) is highly contagious and virulent in common carp (Cyprinus carpio). With the aim to develop molecular tools for breeding CyHV-3-resistant carp,we have amplified and sequenced 11 candidate genes for viral disease resistance including TLR2, TLR3, TLR4ba, TLR7, TLR9, TLR21, TLR22, MyD88, TRAF6, type I IFN and IL-1β.For each gene,we initially cloned and sequenced PCR amplicons from 8 to 12 fish (2-3 fish per strain) from the SNP discovery panel.We then identified and evaluated putative SNPs for their polymorphisms in the SNP discovery panel and validated their usefulness for linkage analysis in a full-sib family using the SNaPshot method.Our sequencing results and phylogenetic analyses suggested that TLR3, TLR7 and MyD88 genes are duplicated in the common carp genome.We,therefore,developed locus-specific PCR primers and SNP genotyping assays for the duplicated loci.A total of 48 SNP markers were developed from PCR fragments of the 13 loci (7 single-locus and 3 duplicated genes). Thirty-nine markers were polymorphic with estimated minor allele frequencies of more than 0.1. The utility of the SNP markers was evaluated in one full-sib family and revealed that 20 markers from 9 loci segregated in a disomic and Mendelian pattern and would be useful for linkage nalysis. Fish &Shellfish Immunology 29 (2010) 356-361.Pawapol Kongchum , Yniv Palti , Eric M.Hallerman , Gideon Hulata, Lior David . (Department of Fisheries and Wildlife Sciences,Virginia Polytechnic Institute and State University, Blacksburg,VA 24061,USANational Center for Cool and Cold Water Aquaculture,USDA-ARS,11861 Leetown Road,Kearneysville,WV 25430,USA Institute of Animal Science,Agricultural Research Organization,Volcani Center,P.O. Box 6,Bet Dagan 50250, Israel Department of Animal Sciences, R.H. Smith Faculty of Agriculture,Food and Environment,The Hebrew University of Jerusalem, Rehovot 76100,Israel).