Mitochondrial DNA sequence variation and phylogenetic relationships among Iberian pigs and other domestic and wild pig populations

Nucleotide sequences of mitochondrial DNA (mtDNA) cytochrome B gene (1140 bp) and control region (707 bp) were used to determine the phylogenetic relationships among 51 pig samples representing ancient and current varieties of Iberian pigs (26), Spanish wild boars (seven) and other domestic pigs (18) of cosmopolitan (Duroc, Large White, Landrace, Pietrain and Meishan) and local (Spotted Black Jabugo, Basque and Mangalitza) breeds. A neighbour-joining tree constructed from pairwise distances provide evidence of the European origin of both Iberian pigs and Spanish wild boars. The introgression of Asian mtDNA haplotypes in the genetic pool of the Iberian breed seems unlikely. Four estimates of sequence divergence between European and Asian clades were calculated from the two main domains of the D-loop region and the synonymous and nonsynonymous nucleotide substitutions in the cytochrome B gene. The time since the divergence of pig ancestors was estimated at about 600,000 years before present.     

Relationship Among H-FABP Gene Polymorphism, Intramuscular Fat Content, and Adipocyte Lipid Droplet Content in Main Pig Breeds with Different Genotypes in Western China

H-FABP (Heart fatty acid-binding protein), a member of FABP family, plays an essential role in long-chain fatty acid uptake and metabolic homeostasis. Its role in pig intramuscular fat content remains poorly understood, especially in local pig breeds in western China. In this study, the genetic variations of 5′-upstream region and the second intron in porcine H-FABP gene were investigated by PCR-RFLP in 256 pigs including Duroc, Large White, Landrace, Neijiang, Rongchang, Bamei pig, Hanjiang Black, Hanzhong White, and the wild ones. The effect of H-FABP gene on the IMF content was analyzed by the least square method. Lipid droplet morphology and content in adipocytes cultured from pigs with different H-FABP genotypes, were studied by oil red O staining and a triglyceride assay kit. Results showed a Hinf I -RFLP in these eight pig breeds and wild pigs, among which Large white, Bamei pig, Hanjiang Black, Hanzhong White, and wild pigs presented with low polymorphism while the other breeds had intermediate polymorphism. There was no Hae III or Msp I -RFLPs in the four Chinese local pig breeds tested, but Duroc, Landrace, Large White, Hanzhong White and wild pig had polymorphism. Landrace, Large White and wild pigs had low levels of Hae III-and Msp I -RFLP, whereas others had intermediate polymorphism. H-FABP genotypes significantly affected the IMF content (P<0.05). The IMF content ordered by H-FABP genotypes were HH>Hh>hh, DD<Dd<dd, and AA<Aa<aa. The genetic effect values were 3.89, 3.42, 3.17, 2.27, 2.49, 2.91, 2.28, 2.70, and 2.95, respectively. Fat deposition in adipocytes was stronger in the HH, dd and aa genotypes than in others. The results suggest that porcine meat quality may be improved by increasing the frequency of genotype aa-dd-HH in pig breeds.     

Polymorphism of mitochondrial DNA in pigs based on restriction endonuclease cleavage patterns

Restriction endonuclease cleavage patterns of mitochondrial DNA (mtDNA) of pigs and Japanese wild boars were analyzed using 17 enzymes which recognize six nucleotides. The map of cleavage sites was made by double-digestion methods. Polymophism of mtDNA was detected in the digestion by BglII, EcoRV, ScaI, and StuI. The restriction cleavage patterns were identical among the breeds of Landrace, Hampshire, Duroc I, and Large White I (A type). The patterns of Large White II were the same as those of Japanese wild boars (B type). A difference between the A type and the B type of mtDNA was found in the case of three restriction enzymes, BglII, ScaI, and StuI, and the nucleotide alterations between them were estimated as more than six. On the other hand, a difference between mtDNA from almost all pigs and mtDNA from Duroc II was detected using EcoRV. We suggest that the difference of mtDNA between the A type and the B type of mtDNA could result from the different origin of boars, that is, whether they were of European or Asian origin.     

Comparative evaluation of genomic inbreeding parameters in seven commercial and autochthonous pig breeds

Single nucleotide polymorphism (SNP) genotyping tools, which can analyse thousands of SNPs covering the whole genome, have opened new opportunities to estimate the inbreeding level of animals directly using genome information. One of the most commonly used genomic inbreeding measures considers the proportion of the autosomal genome covered by runs of homozygosity (ROH), which are defined as continuous and uninterrupted chromosome portions showing homozygosity at all loci. In this study, we analysed the distribution of ROH in three commercial pig breeds (Italian Large White, n = 1968; Italian Duroc, n = 573; and Italian Landrace, n = 46) and four autochthonous breeds (Apulo-Calabrese, n = 90; Casertana, n = 90; Cinta Senese, n = 38; and Nero Siciliano, n = 48) raised in Italy, using SNP data generated from Illumina PorcineSNP60 BeadChip. We calculated ROH-based inbreeding coefficients (F_ROH) using ROH of different minimum length (1, 2, 4, 8, 16 Mbp) and compared them with several other genomic inbreeding coefficients (including the difference between observed and expected number of homozygous genotypes (F_HOM)) and correlated all these genomic-based measures with the pedigree inbreeding coefficient (F_PED) calculated for the pigs of some of these breeds. Autochthonous breeds had larger mean size of ROH than all three commercial breeds. F_HOM was highly correlated (0.671 to 0.985) with F_ROH measures in all breeds. Apulo-Calabrese and Casertana had the highest F_ROH values considering all ROH minimum lengths (ranging from 0.273 to 0.189 and from 0.226 to 0.152, moving from ROH of minimum size of 1 Mbp (F_ROH1) to 16 Mbp (F_ROH16)), whereas the lowest F_ROH values were for Nero Siciliano (from 0.072 to 0.051) and Italian Large White (from 0.117 to 0.042). F_ROH decreased as the minimum length of ROH increased for all breeds. Italian Duroc had the highest correlations between all F_ROH measures and F_PED (from 0.514 to 0.523) and between F_HOM and F_PED (0.485). Among all analysed breeds, Cinta Senese had the lowest correlation between F_ROH and F_PED. This might be due to the imperfect measure of F_PED, which, mainly in local breeds raised in extensive production systems, cannot consider a higher level of pedigree errors and a potential higher relatedness of the founder population. It appeared that ROH better captured inbreeding information in the analysed breeds and could complement pedigree-based inbreeding coefficients for the management of these genetic resources.     

Next generation semiconductor based sequencing of bitter taste receptor genes in different pig populations and association analysis using a selective DNA pool‐seq approach

Taste perception in animals affects feed intake and may influence production traits. In particular, bitter is sensed by receptors encoded by the family of TAS2R genes. In this research, using a DNA pool‐seq approach coupled with next generation semiconductor based target resequencing, we analysed nine porcine TAS2R genes (TAS2R1, TAS2R3, TAS2R4, TAS2R7, TAS2R9, TAS2R10, TAS2R16, TAS2R38 and TAS2R39) to identify variability and, at the same time, estimate single nucleotide polymorphism (SNP) allele frequencies in several populations and testing differences in an association analysis. Equimolar DNA pools were prepared for five pig breeds (Italian Duroc, Italian Landrace, Pietrain, Meishan and Casertana) and wild boars (5–10 individuals each) and for two groups of Italian Large White pigs with extreme and divergent back fat thickness (50 + 50 pigs). About 1.8 million reads were obtained by sequencing amplicons generated from these pools. A total of 125 SNPs were identified, of which 37 were missense mutations. Three of them (p.Ile53Phe and p.Trp85Leu in TAS2R4; p.Leu37Ser in TAS2R39) could have important effects on the function of these bitter taste receptors, based on in silico predictions. Variability in wild boars seems lower than that in domestic breeds potentially as a result of selective pressure in the wild towards defensive bitter taste perception. Three SNPs in TAS2R38 and TAS2R39 were significantly associated with back fat thickness. These results may be important to understand the complexity of taste perception and their associated effects that could be useful to develop nutrigenetic approaches in pig breeding and nutrition.     

H2AFZ,RNF4 and NR4A1 loci are associated with boar semen quality by population association studies

Abstract

Spermatogenesis is a complex process regulated by many genes. In this study, H2AFZ, RNF4 and NR4A1 genes were selected as candidate genes for boar semen quality traits based on their functions during spermatogenesis, and the associations of three loci (H2AFZ c.192?+?210–192?+?213delCGAT, RNF4 c.374?+?358 T?>?C and NR4A1 c.956?+?796 A?>?G) with sperm quality traits were analyzed in Duroc (n?=?185), Large White (n?=?87) and Landrace (n?=?49) pig populations. The results showed H2AFZ c.192?+?210–192?+?213delCGAT AA boars produced 1.52% lower abnormal sperm rate (ASR) than AB boars in Landrace pigs (p?<?0.05); RNF4 c.374?+?358?TC boars produced 0.31?×?10⁸/ml higher sperm concentration (SCON) than CC boars (p?<?0.05) in Large White pigs; NR4A1 c.956?+?796 A?>?G was associated with ASR in Duroc and Large White pigs and was associated with sperm motility (MOT) in Large White and Landrace pigs. This study indicated the H2AFZ, RNF4 and NR4A1 loci were the potential molecular markers for improving the semen quality traits in boars.     

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

The improvement of carcass quality is one of the main breeding goals in pig production. To select appropriate breeding animals, it is of major concern to exactly and reliably analyze the body composition in vivo. Therefore, the objective of the study was to examine whether the combination of dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) offers the opportunity to reliably analyze quantitative and qualitative body composition characteristics of different pig breeding groups in vivo. In this study, a total of 77 pigs were studied by DXA and MRI at an average age of 154 days. The pigs originated from different autochthonous or conventional breeds or crossbreeds and were grouped into six breed types: Cerdo Ibérico (Ib); Duroc × Ib (Du_Ib); White Sow Lines (WSL, including German Landrace and German Large White); Hampshire/Pietrain (Pi_Ha, including Hampshire, Pietrain × Hampshire (PiHa) and Pietrain × PiHa); Pietrain/Duroc (Pi_Du, including Pietrain × Duroc (PiDu) and Pietrain × PiDu); crossbred WSL (PiDu_WSL, including Pietrain × WSL and PiDu × WSL). A whole-body scan was performed by DXA with a GE Lunar DPX-IQ in order to measure the amount and percentage of fat tissue (FM; %FM), lean tissue (LM; %LM) and bone mineral, whereas a Siemens Magnetom Open with a large body coil was used for MRI in the thorax region between 13th and 14th vertebrae in order to measure the area of the loin (LA) and the above back fat area (FA) of both body sides. A GLM procedure using SAS 9.2 was used to analyze the data. As expected, the native breed Ib followed by Du_Ib crossbreeds showed the highest %FM (27.2%, 25.0%) combined with the smallest LA (46.2 cm², 73.6 cm²), whereas Ib had the lowest BW at an average age of 154 days. Pigs with Pi_Ha origin presented the least %FM (12.4%) and largest LA (99.5 cm²). The WSL and PiDu_WSL showed an intermediate body composition. Therefore, it could be concluded that DXA and MRI and especially their combination are very suitable methods to reliably identify differences in body composition and carcass traits among different pig lines in vivo.     

Next Generation Semiconductor Based-Sequencing of a Nutrigenetics Target Gene (GPR120) and Association with Growth Rate in Italian Large White Pigs

The GPR120 gene (also known as FFAR4 or O3FAR1) encodes for a functional omega-3 fatty acid receptor/sensor that mediates potent insulin sensitizing effects by repressing macrophage-induced tissue inflammation. For its functional role, GPR120 could be considered a potential target gene in animal nutrigenetics. In this work we resequenced the porcine GPR120 gene by high throughput Ion Torrent semiconductor sequencing of amplified fragments obtained from 8 DNA pools derived, on the whole, from 153 pigs of different breeds/populations (two Italian Large White pools, Italian Duroc, Italian Landrace, Casertana, Pietrain, Meishan, and wild boars). Three single nucleotide polymorphisms (SNPs), two synonymous substitutions and one in the putative 3′-untranslated region (g.114765469C > T), were identified and their allele frequencies were estimated by sequencing reads count. The g.114765469C > T SNP was also genotyped by PCR-RFLP confirming estimated frequency in Italian Large White pools. Then, this SNP was analyzed in two Italian Large White cohorts using a selective genotyping approach based on extreme and divergent pigs for back fat thickness (BFT) estimated breeding value (EBV) and average daily gain (ADG) EBV. Significant differences of allele and genotype frequencies distribution was observed between the extreme ADG-EBV groups (P < 0.001) whereas this marker was not associated with BFT-EBV.     

西部地区主要猪种和野猪H-FABP基因分子标记

利用PCR-RFLP(Hinf I、Hae Ⅲ和Msp I 3种限制性内切酶)分子标记技术,检测了杜洛克猪、长白猪、大白猪、内江猪、荣昌猪、汉江黑猪、汉中白猪、八眉猪和野猪共计265头猪H-FABP基因5′-上游区和第二内含子区的遗传变异,并利用最小二乘模型分析了H-FABP基因对猪肌内脂肪含量的遗传效应。结果表明：（1）在Hinf I-RFLP位点上,上述品种和野猪均存在多态性,其中大白猪、八眉猪、汉江黑猪、汉中白猪和野猪表现为低度多态,杜洛克、长白猪、内江猪和荣昌猪为中度多态;除汉江黑猪（P<0.05）和野猪（P<0.01）外,其他猪种基因频率和基因型频率都处于Hardy-Weinderg平衡状态（P>0.05）;而在Hae Ⅲ-RFLP和Msp I-RFLP位点上,仅内江猪、荣昌猪、汉江黑猪和八眉猪为单态;（2）9种基因型对肌内脂肪（IMF）含量的影响,HH>Hh>hh,DD相似文献   

Associations of functional candidate genes derived from gene-expression profiles of prenatal porcine muscle tissue with meat quality and muscle deposition

Ten genes (ANK1, bR10D1, CA3, EPOR, HMGA2, MYPN, NME1, PDGFRA, ERC1, TTN), whose candidacy for meat-quality and carcass traits arises from their differential expression in prenatal muscle development, were examined for association in 1700 performance-tested fattening pigs of commercial purebred and crossbred herds of Duroc, Pietrain, Pietrain x (Landrace x Large White), Duroc x (Landrace x Large White) as well as in an experimental F(2) population based on a reciprocal cross of Duroc and Pietrain. Comparative sequencing revealed polymorphic sites segregating across commercial breeds. Genetic mapping results corresponded to pre-existing assignments to porcine chromosomes or current human-porcine comparative maps. Nine of these genes showed association with meat-quality and carcass traits at a nominal P-value of < or = 0.05; PDGFRA revealed no association reaching the P < or = 0.05 threshold. In particular, HMGA2, CA3, EPOR, NME1 and TTN were associated with meat colour, pH and conductivity of loin 24 h postmortem; CA3 and MYPN exhibited association with ham weight and lean content (FOM) respectively at P-values of < 0.003 that correspond to false discovery rates of < 0.05. However, none of the genes showed significant associations for a particular trait across all populations. The study revealed statistical-genetic evidence for association of the functional candidate genes with traits related to meat quality and muscle deposition. The polymorphisms detected are not likely causal, but markers were identified that are in linkage disequilibrium with causal genetic variation within particular populations.     

Distribution of the CD4 Alleles in Sus scrofa Demonstrates the Genetic Profiles of Western Breeds and Miniature Pigs

Widely used antipig CD4 monoclonal antibodies (mAbs) fail to recognize CD4 alleles characteristic of miniature pig lines such as the National Institutes of Health (NIH) miniature pigs and microminipigs. We surveyed polymorphisms in the coding sequence of the porcine CD4 gene among Western and Oriental pig breeds and Japanese wild boars and investigated their distribution. Of the 13 alleles that we identified among the 47 animals, 2 in group I and 3 in group II were found exclusively in Western breed pigs. Group IV alleles, which included mAb-nonbinding alleles, were found frequently in Oriental breed pigs, suggesting that the mAb-nonbinding allele arose from the gene pool of Oriental pigs. Group IV alleles were also found in Duroc and Large White pigs, suggesting genetic inflow from Oriental pig breeds into Western breeds. Comparison of the CD4 sequences of species in Cetartiodactyla suggested that the group IV alleles in Sus scrofa occurred before the divergence of this species from the other artiodactyls. The different antibody specificities of the various CD4 alleles may facilitate the discrimination of T-cell populations in transplantation studies using miniature pigs. The significance of the preservation of CD4 polymorphisms to immune function in pigs warrants further investigation.     

西部地区主要猪种H-FABP基因多态性,IMF含量及不同基因型脂肪细胞脂滴量的关系

H-FABP是FABP家族成员之一,在长链脂肪酸的吸收和代谢平衡中发挥关键作用,但它对猪IMF含量的影响还知之甚少,对中国西部地区的猪种更是如此.文章利用PCR-RFLP（HinfⅠ、HaeⅢ和Msp Ⅰ 3种限制性内切酶）分子标记技术,检测了杜洛克猪、长白猪、大白猪、内江猪、荣昌猪、汉江黑猪、汉中白猪、八眉猪和野猪共计265头猪H-FABP基因5＇-上游区和第二内含子区的遗传变异,利用最小二乘模型分析了H-FABP基因对猪肌内脂肪含量的遗传效应,并运用猪脂肪细胞培养,油红O染色和TG测定等技术检测了H-FABP基因不同基因型脂肪细胞内脂滴的形态和沉积的量.结果表明：（1）在HinfⅠ-RFLP位点上,上述品种和野猪均存在多态性,其中大白猪、八眉猪、汉江黑猪、汉中白猪和野猪表现为低度多态,杜洛克、长白猪、内江猪和荣昌猪为中度多态;除汉江黑猪（P＜0.05）和野猪（P＜0.01）外,其他猪种基因频率和基因型频率都处于Hardy-Weinderg平衡状态（P＞0.05）;而在HaeⅢ-RFLP和Msp Ⅰ-RFLP位点上,仅内江猪、荣昌猪、汉江黑猪和八眉猪为单态;（2）9种基因型对肌内脂肪（IMF）含量的影响,HH＞Hh＞hh,DD＜Dd＜dd,AA＜Aa＜aa,遗传效应值分别为：3.89,3.42,3.17,2.27,2.49,2.91,2.28,2.70,2.95,H-FABP基因可显著地提高IMF含量（P＜0.05）;（3）aaddHH型的脂肪细胞脂滴的形态,密度和含量与其他基因型细胞差异显著（P＜0.05）.结果提示：可通过提高＂aaddHH＂基因型的频率来增加IMF含量,达到改善猪肉质的目的.     

New SNP of the porcine Perilipin 2 (<Emphasis Type="Italic">PLIN2</Emphasis>) gene,association with carcass traits and expression analysis in skeletal muscle

PLIN2 (perilipin 2) is a cytosolic protein that promotes the formation and stabilization of the intracellular lipid droplets, organelles involved in the storage of lipid depots. Porcine PLIN2 gene represents a biological and positional candidate for fat deposition, a polygenic trait that affects carcass and meat quality. The aim of the present study was to screen PLIN2 gene for polymorphisms, to evaluate the association with carcass quality traits, and to investigate the gene expression in skeletal muscle. Six new single nucleotide polymorphisms (SNP) were detected by sequencing 32 samples from five pig breeds (Italian Large White, Italian Duroc, Italian Landrace, Belgian Landrace, Pietrain). Two SNP localized in introns, two in the 3′-untranslated region (UTR), and two missense SNP were found in exons. A 3′-UTR mutation (GU461317:g.98G>A), genotyped in 290 Italian Duroc pigs by High Resolution Melting, resulted significantly associated (P < 0.01) with average daily gain, feed conversion ratio, lean cuts and hams weight estimated breeding values. PLIN2 gene expression analysis in skeletal muscle of Italian Large White and Italian Duroc pigs divergent for backfat thickness and visible intermuscular fat showed a trend of higher expression level in pigs with higher intermuscular fat. These results suggest that PLIN2 can be a marker for carcass quality in pigs. Further investigation at both gene and protein level could elucidate its role on fat deposition.     

用焦磷酸测序技术研究猪线粒体细胞色素B基因单倍型

选择43头大白猪,79头长白猪,66头皮特兰猪和60头清平猪作试验材料,采用焦磷酸测序技术分析猪线粒体细胞色素b(CytB)基因单倍型。研究结果显示CytB基因可分为4种单倍型E1,E2,A1和A2。清平猪仅存在于A1单倍型(100%),大白猪和长白猪存在于E1(49.19%,79.25%)和A1(55.81%,20.25%)单倍型,皮特兰则存在于E1(57.58%)和A2(42.42%)单倍型。 Abstract：To detect porcine mitochondrial cytochrome b (CytB) gene haplotypes, Pyrosequencing, which is a novel DNA sequencing method, has been used to analyze SNPs selected Large White, Landrace, Pietrain and Qingping pigs. The pyrosequencing analysis of CytB gene displayed four distinct haplotypes E1, E2, A1 and A2 respectively. Qingping pigs are only present in haplotype A1, Large White and Landrace pigs are present in haplotype E1 and A1, and Pietrain pigs are present in haplotupe E1 and A2.     

Identification of mitochondrial markers for genetic traceability of European wild boars and Iberian and Duroc pigs

Iberian pigs and wild boars are the source of highly priced meat and dry-cured products. Iberian maternal origin is mandatory for labeled Iberian products, making necessary the authentication of their maternal breed origin. Discrimination between wild and domestic pig maternal origin may be useful to distinguish labeled wild boar meat obtained from hunting or farming. In order to detect useful polymorphisms to trace Iberian, Duroc and wild boar maternal lineages, we herein investigated the complete porcine mitochondrial DNA (mtDNA) using three complementary approaches. Near-complete mtDNA sequences (16989 bp), excluding the minisatellite present in the displacement loop region (D-loop), were successfully determined in six Iberian pigs, two Duroc and six European wild boars. To complete the mtDNA analysis, the D-loop minisatellite region was also analyzed in the same set of samples by amplification and capillary electrophoresis detection. Finally, the frequencies of Asian and European Cytochrome B (Cyt B) haplotypes were estimated in Iberian (n = 96) and Duroc (n = 125) breeds. Comparison of near-complete mtDNA sequences revealed a total of 57 substitutions and two Indels. Out of them, 32 polymorphisms were potential Iberian markers, 10 potential Duroc markers and 16 potential wild boar markers. Fourteen potential markers (five Iberian and nine Duroc), were selected to be genotyped in 96 Iberian and 91 Duroc samples. Five wild boar potential markers were selected and tested in samples of wild boars (73) and domestic pigs including: 96 Iberian, 16 Duroc, 16 Large White and 16 Landrace. Genotyping results showed three linked markers (m.7998C>T, m.9111T>C, m.14719A>G) absent in Duroc and present in Iberian pigs with a frequency 0.72. Six markers (m.8158C>T, m.8297T>C, m.9230G>A, m.11859A>G, m.13955T>C, m.16933T>C), three of them linked, were absent in Iberian pigs and present in Duroc with a joint frequency of almost 0.50. Finally three linked markers (m.7188G>A, m.9224T>C, m.15823A>G) were solely detected in wild boars with a frequency 0.22. The D-loop minisatellite results showed overlapping ranges of fragment sizes and suggested heteroplasmy, a result that nullify the use of this region for the development of breed diagnostic markers. The Cyt B haplotype results showed the presence of European haplotypes in Iberian while one of the Asian haplotypes was detected in Duroc with a frequency 0.22, linked to the Duroc marker m.9230G>A. Our results are valuable to resolve the problems of Iberian and wild boar maternal origin determination but additional markers are required to achieve totally useful genetic tests.     

Red and blond Mangalitza pigs display a signature of divergent directional selection in the SLC45A2 gene

The Mangalitza lard‐type pig breed is well known for its fat appearance and curly hair, and it is mainly distributed in Eastern Europe. Four main lines were created in the nineteenth century by artificial selection: Blond Mangalitza, Black Mangalitza, Swallow‐Belly Mangalitza and Red Mangalitza. The Swallow‐Belly line has a black coat combined with yellow‐blond throat and underbelly. In the current work, we aimed to investigate if the colourations of Mangalitza pigs are genetically determined by one or a few loci whose frequencies have been modified by artificial selection. The results of selection scans, with Hap FLK and BayeScan , and of a GWAS for coat colour highlighted the existence of one region on SSC16 (18–20 Mb) with potential effects on hair pigmentation (Red vs. Blond contrast). The analysis of the gene content of this region allowed us to detect the solute carrier family 45 member 2 (SLC45A2) locus as a candidate gene for this trait. The polymorphism of the SLC45A2 locus has been associated with reduced levels or the absence of melanin in several mammalian species. The genotyping of four missense polymorphisms evidenced that rs341599992:G > A and rs693695020:G > A SNPs are strongly but not fully associated with the red and blond coat colours of Mangalitza pigs, a result that was confirmed by performing a haplotype association test. The near fixation of alternative SLC45A2 genotypes in Red and Blond Mangalitza pigs provides a compelling example of the consequences of a divergent directional selection for coat colour in a domestic species.     

Differences among breeds and manifestation of heterosis in AI boar sperm output

A total of 271,547 records of semen collections were utilized to appraise sperm characteristics of 3319 boars belonging to eight breeds: Czech Large White (CLW), Czech Landrace (CLA), Prestice Black-Pied (PBP), Czech Meat Pig (CM), Hampshire (HA), Duroc (DC), Pietrain (PN), Large White (LW), and various crosses of these breeds. The data was collected over 8 years (1990-1997) from insemination stations for boars in the Czech Republic. The assessment of sperm output was based on semen volume, number of total spermatozoa and number of viable spermatozoa. A linear model was used for statistical analysis included fixed effects of breed or crossbred combinations, boar within breed or crossbred combinations, year-season, and linear and quadratic regression on age of boars at collection and on interval between collections. The average semen volume of boars ranged from 161 to 349 ml, number of total spermatozoa from 81x10(9) to 119x10(9) and number of viable spermatozoa from 60x10(9) to 86x10(9). The lowest values were detected in DC while the highest were observed in LW. In general, sperm output significantly differed across breeds and their crossbreeds. The highest heterosis effect for semen volume was 30.6% (HA x PN), for number of total spermatozoa 18.2% (HA x PN) and 10.4% for number of viable spermatozoa (CLA x DC). Sperm output varied with season, including high values in autumn and winter and low ones in spring and summer.     

Association of Porcine IGF Binding Protein-5 Gene with Meat Quality

IGFBP-5 is a member of the IGF families. Using PCR-SSCP, genotypic and allelic frequencies were analyzed in 18 pig breeds (n = 600). The association between haplotypes and production performance was analyzed in a Jinhua × Pietrain population family (n = 212, total 24 traits). Two SNPs (T199C and G485A) within the gene were analyzed. The breeds had different genotypic and allelic frequencies. Typically, the Chinese native pig breeds carried a higher allele C and G frequency (over 50%) than those of the European pigs, and only Guangdong Large White and wild boar were at Hardy–Weinberg equilibrium. The pigs carrying the CG haplotype had higher hue, loin, and thigh pH1 values than pigs with the TA haplotype, and pigs with the TA haplotype had the lowest loin pH2 value and highest color-a value among the haplotypes. It is proposed that the IGFBP-5 gene is associated with the variation in meat quality, especially in pH value together with other QTLs on chromosome 15.     

SIM1基因第8外显子的SNP对猪背膘厚的影响

采用PCR-SSCP方法检测了约克夏、杜洛克、皮特兰、长白猪、嘉兴黑猪和金华猪6个品种共169头猪的SIM1基因外显子8的SNP及其基因型频率。结果共发现CC、CT、TT 3种基因型, 其基因型频率在国内外猪品种之间具有较大差异。其中, 国内猪种嘉兴黑猪和金华猪只存在TT基因型, 而国外猪种约克夏、杜洛克、皮特兰、长白猪则都存在3种基因型。用最小二乘法分析SNP对长白猪、约克夏猪和杜洛克猪的背膘厚的效应的结果表明, 纯合基因型个体的背膘厚大于杂合基因型个体。SIM1基因型对国外猪种背膘厚有显著效应(P< 0.05), 并且不同部位效应不同。