Mapping quantitative trait loci for innate immune response in the pig

Abstract

The aim of the present study was to detect quantitative trait loci (QTL) for the serum levels of cytokines and Toll-like receptors as traits related to innate immunity in pig. For this purpose, serum concentration of interleukin 2 (IL2), interleukin 10 (IL10), interferon-gamma (IFNG), Toll-like receptor 2 (TLR2) and Toll-like receptor 9 (TLR9) were measured in blood samples obtained from F(2) piglets (n = 334) of a Duroc × Piétrain resource population (DUPI) after Mycoplasma hypopneumoniae (Mh), tetanus toxoid (TT) and Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) vaccination at 6, 9 and 15 weeks of age. Animals were genotyped at 82 genetic markers covering all autosomes. QTL analysis was performed under the line cross F(2) model using QTL Express and 33 single QTL were detected on almost all porcine autosomes. Among the single QTL, eight, twelve and thirteen QTL were identified for innate immune traits in response to Mh, TT and PRRSV vaccine, respectively. Besides single QTL, six QTL were identified by a two-QTL model, of which two for TLR9_TT were in coupling phase and one for IL10_PRRSV was in repulsion phase. All QTL were significant at 5% chromosome-wide level including one and seven at 5% genome- and 1% chromosome-wide level significance. All innate immune traits are influenced by multiple chromosomal regions implying multiple gene action. Some of the identified QTL coincided with previously reported QTL for immune response and disease resistance, and the newly identified QTL are potentially involved in the immune function. The immune traits were also influenced by environmental factors like year of birth, age, parity and litter size. The results of this work shed new light on the genetic background of innate immune response and these findings will be helpful to identify candidate genes in these QTL regions related to immune competence and disease resistance in pigs.

The peripheral blood transcriptome reflects variations in immunity traits in swine: towards the identification of biomarkers

“…However, research aimed at identifying genetic factors that confer relative susceptibility or resistance against diseases in pigs is limited by the lack of sufficient phenotypic observations. Thus, including health traits in the current breeding schemes while limiting loss in long-term selected production traits is a major concern and stands as an emerging trend in pig breeding [1,3-6]. …”

QTL Mapping of Intestinal Neutrophil Variation in Threespine Stickleback Reveals Possible Gene Targets Connecting Intestinal Inflammation and Systemic Health

“…Genomic regions that underlie these complex inflammatory phenotypes associated with neutrophil variation can be identified using genetic mapping in model organisms through the use of mutational screens (Musani et al 2006;Hillhouse et al 2011;Leach et al 2012;Uddin et al 2011;Chen et al 2016;Barry et al 2018). Because of the complex interplay of genetics, microbes and environment, it is also essential to develop outbred mutant models tractable for genetic mapping of natural genetic variants influencing complex phenotypes such as inflammation (Albertson et al 2009;Gasch et al 2016).…”

Investigation of single nucleotide polymorphisms in porcine candidate genes for blood component traits in pigs

“…In previous reports, the SNPs in the QTL region of genes related to PRRSV susceptibility (123,334-124,643 kb) and PRRS viral load (32,123 kb) were SEMA6D (rs318932969), IDH3B (rs10720906), and HSPG2 (rs45432189) (Boddicker et al, 2012;Waide et al, 2017). In the QTL regions (609-21,136 kb) of the interleukin 10 level and Toll-like receptor 9 level genes that affect the resistance to viral disease (Uddin et al, 2011), the SNPs NDUFV1, DPF2, and SSRP1, were found on chromosome 2. In addition, the CSFV antibody level and CD4-positive/CD8-positive leukocyte ratio QTL regions (80,511-106,510 kb) related to classical swine fever (CSF) virus infection were found to contain the CGN and PSMB4 SNPs located on chromosome 4.…”