Association of PPARGC1A and CAPNS1 gene polymorphisms and expression with meat quality traits in pigs

Gene co-expression network analysis for porcine intramuscular fatty acid composition

In pigs, meat quality depends markedly on the fatty acid (FA) content and composition of the intramuscular fat, which is partly determined by the gene expression in this tissue. The aim of this work was to identify the link between muscle gene expression and its FA composition. In an (Iberian × Duroc) × Duroc backcrossed pig population, we identified modules of co-expressed genes, and correlation analyses were performed for each of them versus the phenotypes, finding four relevant modules. Two of the modules were positively correlated with saturated FAs (SFAs) and monounsaturated FAs (MUFAs), while negatively correlated with polyunsaturated FAs (PUFAs) and the omega-6/omega-3 ratio. The gene-enrichment analysis showed that these modules had over-representation of pathways related with the biosynthesis of unsaturated FAs, the Peroxisome proliferator-activated receptor signalling pathway and FA elongation. The two other relevant modules were positively correlated with PUFA and the n-6/n-3 ratio, but negatively correlated with SFA and MUFA. In this case, they had an over-representation of pathways related with fatty and amino acid degradation, and with oxidative phosphorylation. Using a graphical Gaussian model, we inferred a network of connections between the genes within each module. The first module had 52 genes with 87 connections, and the most connected genes were ADIPOQ, which is related with FA oxidation, and ELOVL6 and FABP4, both involved in FA metabolism. The second module showed 196 genes connected by 263 edges, being FN1 and MAP3K11 the most connected genes. On the other hand, the third module had 161 genes connected by 251 edges and ATG13 was the top neighbouring gene, while the fourth module had 224 genes and 655 connections, and its most connected genes were related with mitochondrial pathways. Overall, this work successfully identified relevant muscle gene networks and modules linked with FA composition, providing further insights on how the physiology of the pigs influences FA composition.

Transcriptomics and metabolomics reveal improved performance of Hu sheep on hybridization with Southdown sheep

Consumers are increasingly demanding high-quality mutton. Cross breeding can improve meat quality and is widely used in sheep breeding. However, little is known about the molecular mechanism of cross breeding sheep meat quality. In this study, male Southdown and female Hu sheep were hybridized. The slaughter performance and longissimus dorsi quality of the 6-month-old hybrid offspring were measured, and the longissimus dorsi of the hybrid offspring was analyzed by transcriptomics and metabolomics to explore the effect of cross breeding on meat quality. The results showed that the production performance of Southdown × Hu F1 sheep was significantly improved, the carcass fat content was significantly decreased, and the eating quality of Southdown × Hu F1 sheep were better. Compared with the HS group (Hu × Hu), the NH group (Southdown × Hu) had 538 differentially expressed genes and 166 differentially expressed metabolites (P < 0.05), which were significantly enriched in amino acid metabolism and other related pathways. Up-regulated genes METTL21C, PPARGC1A and down-regulated gene WFIKKN2 are related to muscle growth and development. Among them, the METTL21C gene, which is related to muscle development, was highly correlated with carnosine, a metabolite related to meat quality (correlation > 0.6 and P < 0.05). Our results provide further understanding of the molecular mechanism of cross breeding for sheep muscle growth and meat quality optimization.

Identification of breed-specific genomic variants in Colombian Creole pig breeds by whole-genome sequencing

Dissecting genetic variation of local breeds is important for the success of conservation. In this research, we investigated the genomic variation of Colombian Creole (CR) pigs, with a focus on the breed-specific variants in the exonic region of 34 genes with reported effects on adaptive and economic traits. Seven individuals of each of the three CR breeds (CM, Casco de Mula; SP, San Pedreño; and ZU, Zungo) were whole-genome sequenced along with 7 Iberian (IB) pigs and 7 pigs of each of the four most used cosmopolitan (CP) breeds (Duroc, Landrace × Large White, and Pietrain). Molecular variability in CR (6,451,218 variants; from 3,919,242, in SP, to 4,648,069, in CM) was comparable to that in CP, but higher than in IB. For the investigated genes, SP pigs displayed less exonic variants (178) than ZU (254), CM (263), IB (200), and the individual CP genetic types (201 to 335). Sequence variation in these genes confirmed the resemblance of CR to IB and indicates that CR pigs, particularly ZU and CM, are not exempt from selective introgression of other breeds. A total of 50 exonic variants were identified as being potentially specific to CR, including a high-impact deletion in the intron between exons 15 and 16 of the leptin receptor gene, which was only found in CM and ZU. The identification of breed-specific variants in genes related to adaptive and economical traits can bolster the understanding of the role of gene-environment interactions on local adaptation and points the way for effective breeding and conservation of CR pigs.

Exploring the growth trait molecular markers in two sheep breeds based on Genome-wide association analysis

Growth traits are quantitative traits controlled by multiple micro-effect genes. we identified molecular markers related to sheep growth traits, which formed the basis of molecular breeding. In this study, we randomly selected 100 Qira Black sheep and 84 German Merino sheep for the blood collection the jugular vein to genotype by using the Illumina Ovine SNP 50K Bead Chip. quality control criteria for statistical analysis were: rejection detection rate < 90% and minimum allele frequency (MAF) < 5%. Then, we performed Genome-wide association studies (GWAS) on sheep body weight, body height, body length, and chest circumference using mixed linear models. After getting 55 SNPs with significant correlation, they were annotated by reference genome of Ovis aries genome (Oar_v4.0) and We obtained a total of 84 candidate genes associated with production traits (BMPR1B, HSD17B3, TMEM63C, etc.). We selected BMPR1B for population validation and found a correlation between the FecB locus and body weight traits. Therefore, this study not only supplements the existing knowledge of molecular markers of sheep growth traits, but also has important theoretical significance and reference value for the mining of functional genes of sheep growth traits.

The potential role of PSMA6 in modulating fat deposition in pigs by promoting preadipocyte proliferation and differentiation

To investigate whether the proteasome subunit alpha 6 (PSMA6) gene has an effect on fat deposition, the gene expression profile was first detected in Berkshire pigs and Jinhua pigs (JHP). The results demonstrated that significantly higher levels of mRNA expression were identified in adipose tissues and the liver. Interestingly, when compared to the longissimus dorsi muscle (LDM) in each breed, it was discovered that the expression levels of the PSMA6 gene in these tissues of JHP were considerably higher than those in Berkshire pigs. Meantime, some significant correlations of PSMA6 mRNA expression in lipid metabolism-related tissues such as the liver and LDM with the marbling score, as well as the content of intramuscular fat (IMF), in pigs were found by correlation coefficient analysis. To further explore the effects of PSMA6 expression on fat deposition, we performed PSMA6 overexpression in 3T3-L1 cells via Lentivirus infection. Our results indicated that PSMA6 could promote cell proliferation and accelerate cell division. It was also found that the transcription factors CCAAT/enhancer-binding protein alpha (CEBPA) and peroxisome proliferator-activated receptor gamma (PPARG), as well as the key genes related to adipogenesis, were upregulated, while the genes related to fat oxidation were significantly downregulated, which indicated that the PSMA6 gene could stimulate the differentiation of preadipocytes.

Genetic parameter estimation and gene association analyses for meat quality traits in open-air free-range Iberian pigs

Meat quality of Iberian pigs is defined by the combination of their genetic characteristics and the particular production system. To carry out a genetic analysis of the main meat quality traits, we estimated their heritabilities, genetic correlations and the association effects of 32 selected SNPs of 12 candidate genes. A total of ten traits were measured in longissimus dorsi samples from 1,199 Iberian pigs fattened in the traditional free-range system: water holding capacity (thawing, cooking and centrifuge force water losses), instrumental colour (lightness L*, redness a* and yellowness b*), myoglobin content, shear force on cooked meat, and shear force and maximum compression force on dry-cured loin. Estimated heritability values were low to moderate (0.01 to 0.43) being the lowest for L* and the highest for cooking loss. Strong genetic correlations between water holding capacity traits (0.93 to 0.96) and between myoglobin content and a* (0.94) were observed. The association analyses revealed 19 SNPs significantly associated with different traits. Consistent and strong effects were observed between PRKAG3 SNPs (rs319678464G > C and rs330427832C > T), MYH3_rs81437544T > C, CASP3_rs319658214G > T and CTSL_rs332171512A > G and water losses. Also for CAPN1_rs81358667G > A and CASP3_rs319658214G > T and shear force. The SNPs mapping on PRKAG3 showed the highest effects on Minolta colour traits. Genotyping of these SNPs could be useful for the selection of Iberian young boars with similar estimated breeding values for productive traits.

Cloning and Expression Levels of TFAM and TFB2M Genes and their Correlation with Meat and Carcass Quality Traits in Jiaxing Black Pig

The coding sequences (CDS) of TFAM and TFB2M genes from Jiaxing Black Pig (JBP) were first obtained by RT-PCR and DNA-seq in the present study. Sequence analyses showed that the TFAM gene contains a 741-bp CDS region encoding 246 amino acids sharing a 100% homology with the sequence on NCBI, while TFB2M gene contains a CDS region of 1176 bp encoding 391 amino acids with two missense mutations. The results of quantitative Real-Time PCR for TFAM and TFB2M revealed that transcripts of the genes were both presented at the highest levels in spleen tissue followed by liver tissue, while the least levels in longissimus dorsi muscle (LDM), and obviously the higher levels in two adipose tissues than those in LDM tissue (P<0.01). Meanwhile, a total of forty-two JBPs were employed in this experiment to investigate the effect of these two genes on the carcass, meat quality traits and flavor substances such as fatty acids, intramuscular fat (IMF) in LDM. As expected, some strong correlations of gene expression abundance of TFAM and TFB2M mRNA in particular tissues such as liver and LDM with carcass and meat quality traits including marbling score, as well as the content of saturated fatty acid (SFA), in JBP were found.

Investigation of allele-specific expression of genes involved in adipogenesis and lipid metabolism suggests complex regulatory mechanisms of PPARGC1A expression in porcine fat tissues

Background

The expression of genes involved in regulating adipogenesis and lipid metabolism may affect economically important fatness traits in pigs. Allele-specific expression (ASE) reflects imbalance between allelic transcript levels and can be used to identify underlying cis-regulatory elements. ASE has not yet been intensively studied in pigs. The aim of this investigation was to analyze the differential allelic expression of four genes, PPARA, PPARG, SREBF1, and PPARGC1A, which are involved in the regulation of fat deposition in porcine subcutaneous and visceral fat and longissimus dorsi muscle.

Results

Quantification of allelic proportions by pyrosequencing revealed that both alleles of PPARG and SREBF1 are expressed at similar levels. PPARGC1A showed the greatest ASE imbalance in fat deposits in Polish Large White (PLW), Polish Landrace and Pietrain pigs; and PPARA in PLW pigs. Significant deviations of mean PPARGC1A allelic transcript ratio between cDNA and genomic DNA were detected in all tissues, with the most pronounced difference (p < 0.001) in visceral fat of PLW pigs. To search for potential cis-regulatory elements affecting ASE in the PPARGC1A gene we analyzed the effects of four SNPs (rs337351686, rs340650517, rs336405906 and rs345224049) in the promoter region, but none were associated with ASE in the breeds studied. DNA methylation analysis revealed significant CpG methylation differences between samples showing balanced (allelic transcript ratio ≈1) and imbalanced allelic expression for CpG site at the genomic position in chromosome 8 (SSC8): 18527678 in visceral fat (p = 0.017) and two CpG sites (SSC8:18525215, p = 0.030; SSC8:18525237, p = 0.031) in subcutaneous fat.

Conclusions

Our analysis of differential allelic expression suggests that PPARGC1A is subjected to cis-regulation in porcine fat tissues. Further studies are necessary to identify other regulatory elements localized outside the PPARGC1A proximal promoter region.

Electronic supplementary material

The online version of this article (10.1186/s12863-018-0696-6) contains supplementary material, which is available to authorized users.

Diversity across major and candidate genes in European local pig breeds

The aim of this work was to analyse the distribution of causal and candidate mutations associated to relevant productive traits in twenty local European pig breeds. Also, the potential of the SNP panel employed for elucidating the genetic structure and relationships among breeds was evaluated. Most relevant genes and mutations associated with pig morphological, productive, meat quality, reproductive and disease resistance traits were prioritized and analyzed in a maximum of 47 blood samples from each of the breeds (Alentejana, Apulo-Calabrese, Basque, Bísara, Majorcan Black, Black Slavonian (Crna slavonska), Casertana, Cinta Senese, Gascon, Iberian, Krškopolje (Krškopoljski), Lithuanian indigenous wattle, Lithuanian White Old Type, Mora Romagnola, Moravka, Nero Siciliano, Sarda, Schwäbisch-Hällisches Schwein (Swabian Hall pig), Swallow-Bellied Mangalitsa and Turopolje). We successfully analyzed allelic variation in 39 polymorphisms, located in 33 candidate genes. Results provide relevant information regarding genetic diversity and segregation of SNPs associated to production and quality traits. Coat color and morphological trait-genes that show low level of segregation, and fixed SNPs may be useful for traceability. On the other hand, we detected SNPs which may be useful for association studies as well as breeding programs. For instance, we observed predominance of alleles that might be unfavorable for disease resistance and boar taint in most breeds and segregation of many alleles involved in meat quality, fatness and growth traits. Overall, these findings provide a detailed catalogue of segregating candidate SNPs in 20 European local pig breeds that may be useful for traceability purposes, for association studies and for breeding schemes. Population genetic analyses based on these candidate genes are able to uncover some clues regarding the hidden genetic substructure of these populations, as the extreme genetic closeness between Iberian and Alentejana breeds and an uneven admixture of the breeds studied. The results are in agreement with available knowledge regarding breed history and management, although largest panels of neutral markers should be employed to get a deeper understanding of the population's structure and relationships.

A laboratory exercise for detecting microbial contaminants

The development and evaluation of a 6-hours laboratory class, based on capillary electrophoresis (CE) and the detection of microbial contaminants, is described. It can be easily scaled up or down, to suit class sizes up to 188 and completed in a shorter time scale. CE uses narrow-bore fused-silica capillaries to separate a complex array of large and small molecules. A laboratory exercise has been devised to illustrate how CE-based genetic analysis system processes DNA fragment analysis to detect three microbial contaminants. The protocol is relatively inexpensive and uses standard molecular biology reagents and equipment. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):279-284, 2018.

O-GlcNAcylation mediates the control of cytosolic phosphoenolpyruvate carboxykinase activity via Pgc1α

PGC1α is a coactivator of many transcription factors and cytosolic phosphoenolpyruvate carboxykinase (PCK1) is a key enzyme for gluconeogenesis. PGC1α interacts with the transcription factor PPARγ to stimulate PCK1 expression and thus de novo glucose synthesis. These proteins are not only important for central energy metabolism but also for supplying intermediates for other metabolic pathways, including lipidogenesis and protein synthesis and might therefore be important factors in the ethiopathogenesis of metabolic disorders like diabetes but also in other pathologies like cancer. Since polymorphisms in these proteins have been related to some phenotypic traits in animals like pigs and PGC1α G482S polymorphism increases fat deposition in humans, we have investigated the molecular basis of such effects focusing on a commonly studied polymorphism in pig Pgc1α, which changes a cysteine at position 430 (WT) of the protein to a serine (C430S). Biochemical analyses show that Pgc1α WT stimulates higher expression of human PCK1 in HEK293T and HepG2 cells. Paradoxically, Pgc1α WT is less stable than Pgc1α p.C430S in HEK293T cells. However, the study of different post-translational modifications shows a higher O-GlcNAcylation level of Pgc1α p.C430S. This higher O-GlcNAcylation level significantly decreases the interaction between Pgc1α and PPARγ demonstrating the importance of post-translational glycosylation of PGC1α in the regulation of PCK1 activity. This, furthermore, could explain at least in part the observed epistatic effects between PGC1α and PCK1 in pigs.

Fine mapping of a distal chromosome 4 QTL affecting growth and muscle mass in a chicken advanced intercross line

In our previous research, QTL analysis in an F₂ cross between the inbred New Hampshire (NHI) and White Leghorn (WL77) lines revealed a growth QTL in the distal part of chromosome 4. To physically reduce the chromosomal interval and the number of potential candidate genes, we performed fine mapping using individuals of generations F₁₀ , F₁₁ and F₁₂ in an advanced intercross line that had been established from the initial F₂ mapping population. Using nine single nucleotide polymorphism (SNP) markers within the QTL region for an association analysis with several growth traits from hatch to 20 weeks and body composition traits at 20 weeks, we could reduce the confidence interval from 26.9 to 3.4 Mb. Within the fine mapped region, markers rs14490774, rs314961352 and rs318175270 were in full linkage disequilibrium (D' = 1.0) and showed the strongest effect on growth and muscle mass (LOD ≥ 4.00). This reduced region contains 30 genes, compared to 292 genes in the original region. Chicken 60 K and 600 K SNP chips combined with DNA sequencing of the parental lines were used to call mutations in the reduced region. In the narrowed-down region, 489 sequence variants were detected between NHI and WL77. The most deleterious variants are a missense variant in ADGRA3 (SIFT = 0.02) and a frameshift deletion in the functional unknown gene ENSGALG00000014401 in NHI chicken. In addition, five synonymous variants were discovered in genes PPARGC1A, ADGRA3, PACRGL, SLIT2 and FAM184B. In our study, the confidence interval and the number of potential genes could be reduced 8- and 10- fold respectively. Further research will focus on functional effects of mutant genes.

Differences in calpain system, desmin degradation and water holding capacity between commercial Meishan and Duroc × Landrace × Yorkshire crossbred pork

The objective of this study was to examine the differences in calpain system, desmin degradation, pH values and water holding capacity (WHC) between muscles of commercial Meishan and Duroc × Landrace × Yorkshire crossbred pigs. Meishan pork presented better WHC evidenced by lower purge loss at days 1 and 3 and less centrifugation loss at day 1 post mortem (P < 0.05). pH values at 45 min post mortem in Meishan pork were significantly higher compared to crossbred pork (P < 0.05). Calpain-1 messenger RNA (mRNA) expression was lower in Meishan pork compared to that from crossbred pork (P < 0.05). Additionally, calpain-1 activity, the ratio of calpain-1 to calpastatin activity and desmin degradation were lower in Meishan pork compared to those from crossbred pork samples (P < 0.05). The results indicate that the calpain system including mRNA expression and activity were different between commercial Meishan and crossbred pork resulting in difference in the degree of desmin degradation during post mortem aging. pH values at 45 min and 24 h post mortem rather than calpain activity and desmin degradation could explain the higher water holding capacity in commercial Meishan pork.

Allelic variant in the anti-Müllerian hormone gene leads to autosomal and temperature-dependent sex reversal in a selected Nile tilapia line

Owing to the demand for sustainable sex-control protocols in aquaculture, research in tilapia sex determination is gaining momentum. The mutual influence of environmental and genetic factors hampers disentangling the complex sex determination mechanism in Nile tilapia (Oreochromis niloticus). Previous linkage analyses have demonstrated quantitative trait loci for the phenotypic sex on linkage groups 1, 3, and 23. Quantitative trait loci for temperature-dependent sex reversal similarly reside on linkage group 23. The anti-Müllerian hormone gene (amh), located in this genomic region, is important for sexual fate in higher vertebrates, and shows sexually dimorphic expression in Nile tilapia. Therefore this study aimed at detecting allelic variants and marker-sex associations in the amh gene. Sequencing identified six allelic variants. A significant effect on the phenotypic sex for SNP ss831884014 (p<0.0017) was found by stepwise logistic regression. The remaining variants were not significantly associated. Functional annotation of SNP ss831884014 revealed a non-synonymous amino acid substitution in the amh protein. Consequently, a fluorescence resonance energy transfer (FRET) based genotyping assay was developed and validated with a representative sample of fish. A logistic linear model confirmed a highly significant effect of the treatment and genotype on the phenotypic sex, but not for the interaction term (treatment: p<0.0001; genotype: p<0.0025). An additive genetic model proved a linear allele substitution effect of 12% in individuals from controls and groups treated at high temperature, respectively. Moreover, the effect of the genotype on the male proportion was significantly higher in groups treated at high temperature, giving 31% more males on average of the three genotypes. In addition, the groups treated at high temperature showed a positive dominance deviation (+11.4% males). In summary, marker-assisted selection for amh variant ss831884014 seems to be highly beneficial to increase the male proportion in Nile tilapia, especially when applying temperature-induced sex reversal.

Single nucleotide polymorphism scanning and expression of the pig PPARGC1A gene in different breeds

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) is a candidate gene for lean meat production because it plays a key role in lipid metabolism. In this study, SNPs within the porcine PPARGC1A gene were investigated using PCR-sequencing and PCR-RFLP. Quantitative real-time PCR and Western blot were then used to analyze mRNA and protein expression in longissimus dorsi muscle (LM), liver, and backfat tissues of Dianna small-ear pigs (DSP, n = 6), Tibetan pigs (TP, n = 6), and large white pigs (LW, n = 6). Five novel SNPs (g.-1269A>G in the 5'-upstream regulatory region; g.190C>T, g.218C>A and g.234C>A in exon 8; and g.20C>T in intron 10) and three previously identified SNPs (g.417A>T in exon 8; g.56C>A in exon 9; and g.34G>A in intron 9) were found. Of these, only two, g.-1269A>G and g.234C>A, had three different genotypes in the three breeds (DSP, n = 63; TP, n = 51; and LW, n = 52). Expression was highest in LM, modest in the liver, and minimal in backfat. In LM tissue, LW had higher mRNA and protein levels than DSP and TP (P < 0.05), and there was a negative correlation between gene expression and intramuscular fat (IMF) content. LW had numerically higher expression in liver and backfat tissues than DSP and TP, and the differences in protein levels were significant (P < 0.05 in liver, P < 0.01 in backfat). In conclusion, PPARGC1A may play a key role in down-regulating lipid deposition, and the SNPs with differential genotype distribution among the three pig breeds may be related to gene expression and fat deposition.

Molecular heterogeneities of adipose depots - potential effects on adipose-muscle cross-talk in humans, mice and farm animals

Adipose tissue is considered as a major endocrine organ that secretes numerous proteins called adipokines. The heterogeneous nature of adipose tissue in different parts of the body suggests respective heterogeneity of proteomes and secretomes. This review consolidates knowledge from recent studies targeting the diversity of different adipose depots affecting the pattern of secreted adipokines and discusses potential consequences for the cross-talk between adipose and skeletal muscle in humans, rodent models and farm animals. Special attention is paid to muscle-associated fat depots like inter- and intramuscular fat that become focus of attention in the context of the rather new notion of skeletal muscle as a major endocrine organ. Understanding the complexity of communication between adipocytes and skeletal muscle cells will allow developing strategies for improvement of human health and for sustainable production of high quality meat.

Expression patterns of porcine Toll-like receptors family set of genes (TLR1-10) in gut-associated lymphoid tissues alter with age

The aim was to study the expression pattern of the porcine TLR family (TLR1-10) genes in gut-associated lymphoid tissues (GALT) of varying ages. A total of nine clinically healthy pigs of three ages group (1 day, 2 months and 5 months old) were selected for this experiment (three pigs in each group). Tissues from intestinal mucosa in stomach, duodenum, jejunum and ileum and mesenteric lymph node (MLN) were used. mRNA expression of TLRs (1-10) was detectable in all tissues and TLR3 showed the highest mRNA abundance among TLRs. TLR3 expression in stomach, and TLR1 and TLR6 expression in MLN were higher in adult than newborn pigs. The western blot results of TLR2, 3 and 9 in some cases, did not coincide with the mRNA expression results. The protein localization of TLR2, 3 and 9 showed that TLR expressing cells were abundant in the lamina propria, Peyer's patches in intestine, and around and within the lymphoid follicles in the MLN. This expressions study sheds the first light on the expression patterns of all TLR genes in GALT at different ages of pigs.

A single nucleotide polymorphism in the CYP2E1 gene promoter affects skatole content in backfat of boars of two commercial Duroc-sired crossbred populations

The prevention of unpleasant boar taint is the main reason for castration of male piglets. This study aimed to investigate how the malodorous compound skatole is affected by a single nucleotide polymorphism (g.2412 C>T at -586 ATG) in the porcine cytochrome p450 II E1 (CYP2E1) gene. 119 boars of two commercial Duroc-sired crossbred populations raised at different farms were investigated. Skatole and androstenone in backfat averaged 114±125 ng/g and 1206±895 ng/g melted fat, respectively. The frequency of the genotypes CC, CT, and TT was 25, 52, and 23%, respectively. CC boars had the highest average skatole levels (175 ng/g) compared to CT (92 ng/g) and TT (93 ng/g). Applying suggested sensory threshold levels for skatole (>150 ng/g) and androstenone (>2000 ng/g), 30% of the carcasses may be unacceptably tainted while the proportion of tainted carcasses is significantly higher within genotype CC (56.7%) compared to genotypes CT (24.3%) and TT (14.8%). Effective reduction of tainted carcasses appears feasible applying marker assisted selection.