Identification of single nucleotide polymorphism markers associated with bacterial cold water disease resistance and spleen size in XXXX .

@entity5660 @entity4577 @entity4334
@entity4577 ( @entity4577 ) is one of the frequent causes of elevated mortality in salmonid aquaculture. Previously, we identified and validated microsatellites on chromosome Omy19 associated with QTL (quantitative trait loci) for @entity4577 resistance and spleen size in @entity5660 . Recently, SNPs (single @entity4334 polymorphism) have become the markers of choice for genetic analyses in @entity5660 as they are highly abundant, cost-effective and are amenable for high throughput genotyping. The objective of this study was to identify SNP markers associated with @entity4577 resistance and spleen size using both genome-wide association studies (GWAS) and linkage-based QTL mapping approaches. A total of 298 offspring from the two half-sib families used in our previous study to validate the significant @entity4577 QTL on chromosome Omy19 were genotyped with RAD-seq (restriction-site-associated DNA sequencing), and 7,849 informative SNPs were identified. Based on GWAS, 18 SNPs associated with @entity4577 resistance and 20 SNPs associated with spleen size were identified. Linkage-based QTL mapping revealed three significant QTL for @entity4577 resistance. In addition to the previously validated dam-derived QTL on chromosome Omy19, two significant @entity4577 QTL derived from the sires were identified on chromosomes Omy8 and Omy25, respectively. A sire-derived significant QTL for spleen size on chromosome Omy2 was detected. The SNP markers reported in this study will facilitate fine mapping to identify positional candidate genes for @entity4577 resistance in @entity5660 .
