Quantitative trait loci analysis for leg weakness-related traits in a Duroc × Pietrain crossbred population

Abstract

BackgroundLeg weakness issues are a great concern for the pig breeding industry, especially with regard to animal welfare. Traits associated with leg weakness are partly influenced by the genetic background of the animals but the genetic basis of these traits is not yet fully understood. The aim of this study was to identify quantitative trait loci (QTL) affecting leg weakness in pigs.MethodsThree hundred and ten F2 pigs from a Duroc × Pietrain resource population were genotyped using 82 genetic markers. Front and rear legs and feet scores were based on the standard scoring system. Osteochondrosis lesions were examined histologically at the head and the condylus medialis of the left femur and humerus. Bone mineral density, bone mineral content and bone mineral area were measured in the whole ulna and radius bones using dual energy X-ray absorptiometry. A line-cross model was applied to determine QTL regions associated with leg weakness using the QTL Express software.ResultsEleven QTL affecting leg weakness were identified on eight autosomes. All QTL reached the 5% chromosome-wide significance level. Three QTL were associated with osteochondrosis on the humerus end, two with the fore feet score and two with the rear leg score. QTL on SSC2 and SSC3 influencing bone mineral content and bone mineral density, respectively, reached the 5% genome-wide significance level.ConclusionsOur results confirm previous studies and provide information on new QTL associated with leg weakness in pigs. These results contribute towards a better understanding of the genetic background of leg weakness in pigs.

In vivo body composition in autochthonous and conventional pig breeding groups by dual-energy X-ray absorptiometry and magnetic resonance imaging under special consideration of Cerdo Ibérico

“…Leg weakness is generally becoming a concern in the pig industry (Guo et al, 2009). Therefore, it could be helpful to take BMD into consideration for swine selection as suggested by Laenoi et al (2011). They found quantitative trait loci for BMD and BMC in a conventional Duroc 3 Pietrain F2 population on chromosomes 2 and 3 (P , 0.05 on chromosome-wide level).…”

Gene expression profiling of articular cartilage reveals functional pathways and networks of candidate genes for osteochondrosis in pigs

“…Gene identity was assigned to the Affymetrix probe-sets based on BLAST comparisons to the porcine genome sequence [Ensembl_Sscrofa10.2; according to Naraballobh et al (42), updated]; 20,689 of the 24,123 probe-sets on the Affymetrix Porcine GeneChip were localized and annotated. Genes encoding transcripts with significant different abundance between the groups of healthy and affected samples (DE genes) were assigned to the QTL regions for OC lesion scores that were previously obtained in F2 Duroc ϫ Pietrain crossbreed pigs of the same resource population (28). In brief, the association mapping revealed QTL on the confidence region of chromosomes (SSC) 2, 3, 6, 10, and 14 influencing OC scores at articular cartilage.…”

“…A previous QTL study (28) found that OC lesion scores were affected by 5 QTL located on SSC2, 3 Table S6). Genes represented by probe-sets with Ͼ1.5-fold difference in transcript abundance between OC-negative and OC-positive cartilage mapped within the confidence intervals of QTL on SSC 2, 3, and 6 are listed in (Table 3); whereas under the QTL on SSC10 and 14 there were no genes represented by probe-sets with Ն1.5-fold divergence of transcript frequency.…”

“…The heritability of OC or leg weakness was estimated as being low to moderate in different pig breeds (21,22,34,49). Linkage studies in pigs identified numerous quantitative trait loci (QTL) for OC lesions or leg weakness-related traits in pigs (28,31,66). However, knowledge of the molecular processes of the pathogenesis underlying the OC disorder remains limited.…”

“…Therefore, we performed a holistic microarray expression analysis in OC-negative and OC-positive articular cartilage obtained from a porcine experimental Duroc ϫ Pietrain crossbreed population. We further integrated data of the expression study with the results of a previous QTL study, conducted in the same Duroc ϫ Pietrain population (28), as well as with a genomewide association study (GWAS) performed with animals of commercial Large White herds. Assignment of genes with different transcript abundance to QTL regions aids in identifying functional and positional candidate genes associated with the development of articular cartilage OC lesions.…”