Tongcheng Pigs Research Articles

Molecular cloning and characterization of porcine sirtuin genes

The sirtuin family of class III histone deacetylases (HDACs) is named after their homology to yeast silent information regulator 2 (SIR2). SIR2 and its mammalian derivatives (SIRT1-7) play a central role in gene silencing, cell cycle, aging and metabolism. Here we reported cDNA cloning, chromosome mapping,expression and evolutional analysis of sirtuin genes in Sus scrofa (Tongcheng pig). Sequence analysis showed that porcine sirtuin genes contain 7 members designated SIRT1-7. Tissue distribution analysis indicated porcine sirtuin genes ubiquitously expressed but with the highest abundance in brain, spinal cord and genital tissue. In silico and radiation hybrid mapping analysis mapped porcine SIRT1-7 to the chromosomes 14q23,6q11-12, 2q29, 14q19, 7p12, 2q11, and 12p15, respectively. We also isolated and characterized genomic sequence of porcine SIRT1, which spaned a region of 31,834 bp comprising 9 exons ranging in size from 80 bpto 2121 bp. The 5' flanking genomic region preceding an open reading frame of SIRT1 has a TATA box, a small300 bp CpG island and several putative Sp1 and p53 transcription factor binding sites. Moreover, we isolated two novel splicing SIRT6 variants with 346 bp (variant 2) in-frame deletions from lung and 327 bp(variant 3) in-frame deletions from spleen and brain. This is the first systematic report of molecular cloning and characterization of sirtuin genes in pigs, which will be helpful for a better understanding of the physiological role of sirtuin proteins in pigs.

Mapping, Tissue Distribution and Polymorphism of Porcine Retinol Binding Protein Genes (RBP5 and RBP7)

The retinoids (vitamin A and its derivatives) play a critical role in vision, growth, reproduction, cell differentiation and embryonic development. Using the IMpRH panel, porcine cellular retinol binding protein genes 5 and 7 (RBP5 and RBP7) were assigned to porcine chromosomes 5 and 6, respectively. The complete coding sequences (CDS) of the RBP5 and RBP7 genes were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) method, and the deduced amino acid sequences of both genes were compared to human corresponding proteins. The mRNA distributions of the two genes in adult Wuzhishan pig tissues (lung, skeletal muscle, spleen, heart, stomach, large intestine, lymph node, small intestine, liver, brain, kidney and fat) were examined. A total of nine single nucleotide polymorphisms (SNPs) were identified in two genes. Three of these SNPs were analyzed using the polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) method in Laiwu, Wuzhishan, Guizhou, Bama, Tongcheng, Yorkshire and Landrace pig breeds. Association analysis of genotypes of these SNP loci with economic traits was done in our experimental populations. Significant associations of different genotypes of RBPS-A/G 63 , RBPS-A/G 517 and RPBS-T/C intron1-90 loci with traits including maximum carcass length (LM), minimum carcass length (LN), marbling score (MS), back fat thickness at shoulder (SBF), meat color score (MCS) and hematocrit (HCT) were detected. These SNPs may be useful as genetic markers in genetic improvement for porcine production.

Genetic polymorphisms and preliminary association analysis with production traits of the porcine SLC27A4 gene

Solute carrier family 27 (fatty acid transporter), member 4 (SLC27A4) is a fatty acyl-CoA synthetase producing very long chain fatty acid-CoA for lipid metabolic pathways, suggesting that the SLC27A4 gene is a potential candidate gene for traits related to fat deposition in animals. This study was conducted to sequence the genomic region from exon 6 to 12 of porcine SLC27A4 and detect polymorphisms by comparative sequencing. In silico mapping assigned SLC27A4 gene between gene COQ4 (coenzyme Q4 homolog) and URM1 (ubiquitin related modifier 1 homolog) on pig chromosome 1q24-q2.12 where significant QTL affecting backfat depth had previously been identified. Thirty six putative sites of variation were detected, of which 31 polymorphisms including 28 SNPs and 3 indels were located in the intronic region, and 5 in the exonic regions. The g.1777G>A (EU703769) in intron 8 was confirmed by PCR-RFLP using HpaII restriction enzyme and further genotyped in four Chinese native pig breeds (Meishan, Erhualian, Tongcheng and Qingping) and three western meat-type pig breeds (Duroc, Large White and Landrace). Allele G was exclusively present in Tongcheng and Qingping pigs and predominant in the other pig populations analyzed. Significant differences of backfat at rump, body weight at birth and average daily gain on weaning between the AG and GG genotype were observed in Landrace pig population (P < 0.05).

Effect of breed, sex and birth parity on growth, carcass and meat quality in pigs

The effects of breed, sex and birth parity on the traits of growth, carcass and meat quality were investigated in three different breeds including Swedish Landrace, British Large White and an indigenous Chinese breed — Tongcheng pigs. The results indicated that the Swedish Landrace and the British Large White had advantages over the Tongcheng pigs in growth rate, feed conversion rate (FCR) and carcass traits, but had disadvantages in meat quality. In contrast to the British Large White, the Swedish Landrace had higher average daily gain during the trial (ADG2) (877.04 g·day−1 vs. 813.95 g·day−1, P < 0.05), and marbling score (MS) (2.48 vs. 2.02, P < 0.01), larger eye muscle area (EMA) (41.80 cm2 vs. 35.14 cm, P < 0.01) and more efficient feed conversion rate (FCR) (3.06 vs. 3.29, P < 0.05), lower muscle shear force (MSF) (4.20 kgf (1 kgf = 9.80665 N) vs. 4.93 kgf, P < 0.05) and backfat thickness (BF) (all P < 0.01) including live backfat thickness (LBF), average backfat thickness at 3 points in the carcass (ABF), backfat thickness between 6th and 7th ribs (6–7 th BF) and backfat thickness at 10th rib (10 th BF). There was a difference (P < 0.05) only inMS between castrated females (CF) and castrated males (CM). Birth parity affected ADG2 (P < 0.05), some carcass characteristics and meat quality, including CL1 (P < 0.001), CL2 (P < 0.05), BF (ABF, 6–7th BF and 10th BF, all P < 0.001), EMD (P, 0.001), EMA (P < 0.001), percentage of leaf and caul fat (PLC) (P < 0.05), proportion of lean and bone of the ham (PLBH) (P < 0.05), muscle drip loss percentage (DL) (P < 0.05) and intramuscular fat content (IMF) (P < 0.05). The breed-sex interaction only impacted the average daily gain from birth to marketing (ADG1) and DL (both P < 0.05). However, there was no significant effect of sex-parity interaction on all the traits tested.

Full-length coding sequences, polymorphism and chromosomal localizations of the porcine EDG4 and EDG7 genes

EDG4 and EDG7 are identified as cellular receptors for lysophosphatidic acid (LPA), belonging to the endothelial cell differentiation gene (EDG) family of G protein-coupled receptors (GPCR) which play an important role in the function of LPA. In this study, we presented the complete coding sequences of porcine EDG4 and EDG7 genes. The nucleotide sequences and the predicted protein sequences share high sequence identity with other mammals. Spatial expression analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that porcine EDG4 and EDG7 genes are mainly expressed in brain, liver, spleen, lung, kidney, large intestine, small intestine, but absent in muscle tissues. Radiation hybrid mapping data indicated that EDG4 and EDG7 map to q2.1 of pig chromosome 2 (SSC2) and q2.6-3.2 of pig chromosome6 (SSC6), respectively. A T/C single nucleotide polymorphism (SNP) in the coding sequence of porcine EDG4 was identified. A PCR-restriction fragment length polymorphism (PCR-RFLP) method was employed to genotype this locus among Guizhou Miniature, Guangxi Miniature, Laiwu, Wuzhishan, Tongcheng, Landrace and Yorkshire pigs. The association analysis suggested that the EDG4 genotype was associated with carcass length (P < 0.05) and drip loss percentage (P < 0.05) in the experimental population consisting of Tongcheng, Landrace, Yorkshire and two crossbred porcine populations (Wang et al. Biochem Genet (1-2):51-62, 2007).

Sequence Characterization, Polymorphism, and Chromosomal Localizations of the Porcine Capz Genes

CapZ is a widely distributed and highly conserved actin-binding protein that caps the barbed end of actin filaments and nucleates actin polymerization in a Ca(2+)-independent manner. In myofibrils, it is localized in the Z-lines. In this study, we cloned and characterized Capz subunit genes from the pig muscle. The nucleotide sequences and the predicted protein sequences share high sequence identity with other mammalian orthologs. The reverse transcriptase polymerase chain reaction (RT-PCR) revealed that porcine Capzbeta, Capzalpha1, and Capzalpha2 genes are expressed in all 11 tissues studied (liver, spleen, small intestine, large intestine, lymph node, kidney, heart, skeletal muscle, brain, fat, and lung) but in variable amounts. Radiation hybrid mapping data indicated that Capzbeta, Capzalpha1, and Capzalpha2 map to q2.1-2.6 of pig chromosome 6 (SSC6), q1.6-q2.2 of pig chromosome 4 (SSC4), and q1.3-2.3 of pig chromosome 18 (SSC18), respectively. An A/C single nucleotide polymorphism in Capzbeta intron 4 was identified with a HhaI PCR restriction fragment length polymorphism, which showed great allele frequency differences between Guizhou Xiang, Guangxi Bama, Wuzhishan, Tongcheng, Landrace, and Yorkshire pigs. The association analysis suggested that the Capzbeta genotype was associated with leaf fat (P < 0.05) in our experimental population.

Flavour differences of cooked longissimus muscle from Chinese indigenous pig breeds and hybrid pig breed (Duroc × Landrace × Large White)

The objectives of this study were to investigate the flavour quality and volatile aroma compounds of cooked longissimus muscle from five typical Chinese indigenous pig breeds: Lantang (LT), Dahuabai (HB), Laiwu (LW), Rongchang (RC), Tongcheng (TC) and typical hybrid pig breed Duroc × Landrace × Large White (DLW). The chemical compositions of the main meat flavour precursors of the longissimus muscle from all six breeds were also examined. Distinct differences in amino acid composition and fatty acid composition of longissimus muscle, between the breeds, were observed. Among all six breeds, LW and RC had the highest intramuscular fat content and the lowest crude protein content; DLW had the lowest longissimus muscle fat content and the highest crude protein content. One-way analysis of variance showed that 23 volatile compounds were significantly affected by breed. Sensory analysis indicated that cooked longissimus muscle from DLW had the lowest pork flavour intensity and flavour-liking, compared with the Chinese indigenous breeds. LW and HB showed the highest pork flavour intensity and flavour-liking in cooked longissimus muscle.

Molecular characterization of the BTG2 and BTG3 genes in fetal muscle development of pigs

BTG2 and BTG3 are two members of the B-cell translocation gene family with anti-proliferative properties. BTG1 gene in this gene family has been reported to play a key role in muscle growth. In this study, we identified and characterized the porcine BTG2 and BTG3 genes, mapped the two genes to porcine chromosomes, and analyzed their expression differences in the longissimus dorci muscle of 33 dpc (day postconception), 65 dpc and 90 dpc in the lean Landrace and fatty Chinese Tongcheng pig breeds. Expression changes in differentiated C2C12 cells were also investigated with myogenin as internal control. The results showed that the porcine BTG2 and BTG3 genes were mapped on SSC9q21-25 and SSC13q47, respectively. BTG2 gene expressed at high levels in skeletal muscle and heart in both Tongcheng and Landrace pigs whereas BTG3 gene expressed at lower levels in skeletal muscle and heart than in other tissues. Furthermore, BTG3 expressed at higher levels in skeletal muscle of Tonghceng compared with Landrace pig. The expression of BTG2 and BTG3 was significantly different in skeletal muscle among different developmental stages and between the two breeds. Expression analysis in murine myoblast cells showed that both genes were induced in differentiated C2C12 cells, suggesting a role of them in myogenic differentiation. Our study indicated that BTG2 and BTG3, especially BTG3 gene, may be important genes for skeletal muscle growth.

The Porcine FoxO1, FoxO3a and FoxO4 Genes: Cloning, Mapping, Expression and Association Analysis with Meat Production Traits

PoxO1, FoxO3a and FoxO4 belong to the FoxO gene family, which play important roles in the PI3K/PKB pathway. In this study, we cloned the porcine FoxOl, FoxO3a and FoxO4 sequences and assigned them to SSCllpll-15, SSC1p13 and SSC xq13 using somatic cell hybrid panel (SCHP) and radiation hybrid panel (IMpRH). RT-PCR results showed that these three genes are expressed in multiple tissues. Sequencing of PCR products from different breeds identified a synonymous T/C polymorphism in exon 2 of FoxO3a. This FoxO3a single nucleotide polymorphism (SNP) can be detected by AvaII restriction enzyme. The allele frequencies of this SNP were investigated in Dahuabai, Meishan, Tongcheng, Yushan, Large White, and Duroc pigs. Association of the genotypes with growth and carcass traits showed that different genotypes of FoxO3a were associated with carcass length and backfat thickness between 6th and 7th ribs (BTR) and drip loss (p<0.05).

The Effects of Mx1 Locus on Immunity Tracts Components in Large White x Meishan F 2 Offspring

The mouse Myxovirus resistance protein 1 (Mx1) is known to be sufficient to confer resistance to influenza viruses, and genes encoding Myxovirus resistance protein 1 (Mx1) is, therefore, an interesting candidate gene for disease resistance in farm animals. The porcine Mx1 gene has already been identified and characterized based on its homology with mouse Mx1; the full-length coding region of the pig Mx1 gene spans 2 545 bp (M65087) and is organized into 17 exons compared with the human ortholog mRNA. In this study, the exons 9, 10, 11 and introns 6, 9 of the porcine Mx1 gene were cloned and sequenced; two SNPs were identified in exons 9, 10, 11 but none of the SNPs led to an amino acid exchange, and the other eleven variants were detected in introns 6 and 9, respectively. Differences in allele frequency among Meishan, Large White, Tibetan, Tongcheng, Huainan, and Duroc pigs were observed within intron 9, of which an A → G substitution at position 186 was detected as an Msp I PCR-restriction fragment length polymorphism (PCR-RFLP). The association analysis using the Large WhitexMeishan F 2 offspring suggested that the Mx1 genotype was associated with variation in several immunity traits that are of interest in pig breeding. However, further investigations in more populations are needed to confirm the above concept.

LongSAGE analysis of skeletal muscle at three prenatal stages in Tongcheng and Landrace pigs

Transcriptional profiling of Tongcheng and Landrace pigs using long serial analysis of gene expression provides insight into the molecular mechanism underlying differences in muscle growth.

Molecular characterization and association analysis of porcine CA3

Carbonic anhydrase 3 (CA3) is a member of the carbonic anhydrase family, which plays an important role in various cell processes. In this paper, molecular characterization revealed that CA3 genomic DNA consists of seven exons and six introns, spans about 10.5 kb and maps to porcine chromosome 4q11→q14. Results of expression profiles showed that the expression levels of CA3 increased in skeletal muscles from prenatal 33- to 65-day-old Chinese Tongcheng pigs. These levels subsequently decreased to a steady state in prenatal 90-day-old, postnatal 2-day-old, postnatal 28-day-old, and pregnant 65-day-old pigs. The expression patterns of Chinese Tongcheng pig embryos were different from that of Landrace pig embryos. CA3 was expressed at higher levels in skeletal muscle and liver than in kidney, lung, stomach, intestine, and brain, but was not detected in heart and spleen. Statistical analysis showed the CA3 gene polymorphism was different between Chinese indigenous and introduced commercial western pig breeds, and was associated with intramuscular fat content and percentage of ham of pigs.

Subcellular localization, expression patterns, SNPs and association analyses of the porcine HUMMLC2B gene

Myosin regulatory light chain (MLC) regulates myofilament activation via phosphorylation by Ca(2+) dependant myosin light chain kinase. In order to further understand the functions of the porcine fast myosin regulatory light chain gene (HUMMLC2B) in muscle, the subcellular localization, the temporal and spatial distributions of its gene product were analyzed, and the association between the presence of specific polymorphisms and commercial meat traits in pig was also examined. HUMMLC2B was demonstrated to localize both in the cytoplasm and the nucleus by confocal fluorescence microscopy. Real-time PCR further revealed HUMMLC2B expression variation in a waveform manner in the skeletal muscle of both Chinese Tongcheng and Western Landrace pig breeds at days 33, 65 and 90 post coitum (pc). After birth, the expression levels of HUMMLC2B were also found to decrease gradually with age. Our spatial expression analysis showed that HUMMLC2B was highly expressed in the semitendinosus, gastrocnemius, biceps femoris and longissimus dorsi muscles. In contrast, only low levels of expression of this gene were evident in fat, and no expression was detectable in brain, heart, kidney, lung, liver, lymph node, spleen, stomach, or in either large or small intestine. A total of 23 potential polymorphisms, comprising 3 exonic and 20 intronic, were detectable in the porcine HUMMLC2B gene and the G1094A, T1513C, G1876A and T2005G polymorphisms were further analyzed. The significant associations between the T1513C, G1876A and T2005G polymorphisms with marbling score, dressing percent and meat color, respectively, were identified (P < 0.05). Associations with the percentage of leaf fat could also be demonstrated by analysis of haplotypes harboring these three polymorphisms. Our current results thus shed further light on the roles and functions of the HUMMLC2B gene in muscle.

Molecular Characterization and Expression Patterns of Porcine Eukaryotic Elongation Factor 1 A

The eukaryotic elongation factor 1 A (EEF1A) participates in protein synthesis by forming the eEF1A GTP tRNA complex to deliver aminoacyl-tRNA to the A site of ribosomes. This study described cDNA sequences and partial genomic structure of porcine EEF1A1. The porcine EEF1A1 gene encoded a protein with 462 amino acids, which shared complete homology with human, chimpanzee and dog. The temporal expression pattern showed the diversity of EEF1A1 level in mRNA was relatively minor in prenatal embryo skeletal muscle, however, the expression decreased during aging after birth in skeletal muscle of the Chinese Tongcheng pig. The spatial expression patterns indicated that the gene expressed in skeletal muscle, heart, lung, liver, kidney, fat and spleen. In addition, we assigned the gene to porcine chromosome 1 using a radiation hybrid panel.

Germplasm characteristics and conservation of Tongcheng pig: A case study for preservation and utilization of Chinese indigenous pig breeds

SummaryThe paper describes the breed characteristics, production performance including reproduction, growth, carcass and meat quality traits of the Tongcheng pig, one of the indigenous pig breeds suitable for a hybrid maternal line in central China. Based on the field investigation and data statistics from the farm recordings, the Tongcheng pig has early sexual maturity indicators, and the average litter size is 8.5 for first parity and 9.3 and 11.3 for the second and subsequent parities respectively. In a three-way crossing project launched recently, using the Tongcheng pig as the maternal parent and Landrace or Yorkshire pigs as the paternal parent, the performance testing results showed that Tongcheng pigs had a lower growth and meat production performance than these commercial pigs, but had superior meat quality. The production performance of the two crossing groups Landrace/Yorkshire/Tongcheng pigs) (LYT) and Yorkshire/Landrace/Tongcheng pigs) (YLT) were improved in comparison to their parent lines, and the results further indicated that the LYT cross is a tri-crossing style convenient for farm and village areas in central China. Meanwhile, effective management measures taken towards Tongcheng pig preservation, and a genetic diversity evaluation on the Tongcheng pig were reviewed. This paper offers the Tongcheng pig as a case study for the maintenance and utilization of indigenous pigs in China, which is rich in pig breeds but is also confronting the pig resource crisis.

Isolation, Cloning, and Identification of Expressed Sequence Tags from the Backfat Tissue in Duroc and Tongcheng Pigs by mRNA Differential Display

mRNA differential display technique was performed to discuss the differential expression of genes in fat tissue between introduced European and Chinese indigenous pigs. Four anchor primers in combination with five arbitrary primers (20 sets in total) were used and nearly 300 bands were observed in polyacrylamide gel, among which 29 differential display bands were obtained. Twelve of 29 cDNA fragments were identified using reverse Northern dot blot, and subsequently cloned and sequenced. Eight of 12 cDNAs had no matches in GenBank and were submitted to GenBank, and the other 4 showed similarity to identified genes from GenBank. Three among 8 novel ESTs were selected to be further identified by semi-quantitative RT-PCR. In our experiment, silver staining DDRT-PCR and DIG primer DNA labeling reverse Northern dot blot were used to avoid radioactive pollution. The result showed that the expressions of 5 among 8 novel ESTs were stronger in the backfat of Tongcheng pigs and the others were weaker than that in Duroc pigs. These novel ESTs were prepared for selecting genes related to adipose cells.

Assignment of CRSP9, ETF1 and TMEM59 genes to porcine chromosomes

Several porcine cDNA clones were isolated from Chinese Tongcheng pig 55-day fetal longissimus dorsi muscle cDNA library and sequenced (Zhu et al., 2005). After BLAST search in the GenBank non-redundant (nr) sequence database (http://www.ncbi.nlm.nih.gov/BLAST/Blast.cgi), we found and identifi ed these three porcine orthologous genes. Primers to amplify across the putative intron regions were designed based on the pig cDNA sequences after alignment of the pig and human sequences. PCR products were confi rmed by sequencing and then pig-specifi c primers were designed in intron regions. Chromosome location was identifi ed by PCR analysis of the porcine whole genome hybrid panel. Each PCR was performed in duplicate according to the protocol described by Wang et al. (2005). The PCR profi le included 3 min at 94 ° C; 35 cycles of 20 s at 94 ° C, 20 s at 62 ° C, and 20 s at 72 ° C, and a fi nal 5 min extension at 72 ° C. Data analysis was performed through the IMpRH web site (http://www.toulouse.inra.fr/lgc/pig/RH/IMpRH.htm).

Cloning, mapping and association study with carcass traits of the porcine SDHD gene

A 1320-bp cDNA containing the full coding region of the porcine succinate dehydrogenase complex, subunit D (SDHD) gene was obtained by random sequencing of clones from a Chinese Tongcheng pig 55-day fetal longissimus dorsi muscle cDNA library. Analysis of the SDHD gene across the INRA-University of Minnesota porcine radiation hybrid panel indicated close linkage with microsatellite marker SW2401, located on SSC9p21. The open reading frame of this cDNA covers 480 bp and encodes 159 amino acids. The deduced porcine amino acid sequence showed greater similarity with human and bovine protein sequences than with those from mouse and rat. The BLAST analysis of the porcine SDHD to NCBI identified Unigene Cluster Ssc.2586. Possible single nucleotide polymorphisms (SNP) were identified by alignment of expressed sequence tags in the cluster. The polymerase chain reaction (PCR) single strand conformation polymorphism, sequencing, and PCR restriction fragment length polymorphism were used to confirm and detect a synonymous polymorphic MboI site within the open-reading frame. Allele frequencies of this SNP were investigated in two commercial and five Chinese local pig breeds. These five Chinese breeds had very high frequencies for one allele, whereas frequencies of both alleles were intermediate in Large White and Duroc. An association analysis suggested that different SDHD genotypes have significant differences in loin-muscle area (P < 0.01).

Genetic Status of ESR Locus and Other Unidentified Genes Associated with Litter Size in Chinese Indigenous Tongcheng Pig Breed after a Long Time Selection

The Tongcheng pig breed is a famous Chinese indigenous breed. The Ministry of Agriculture of China has filed it as 1 of 19 national key conservation breeds selected from more than 100 Chinese indigenous pig breeds in 2000. In order to improve the reproductive performance, it has been intensively selected to increase the litter size for about 10 years. The population randomly sampled from conservation nucleus of eight families in the Tongcheng pigs was genotyped for identification of their estrogen receptor locus polymorphisms with the PCR-RFLPs method. Only AB heterozygotes and BB homozygotes were detected, and x 2 test demonstrated that the locus was in disequilibrium at a significant level (p<0.05). In the present paper, the litter sizes in different parities were regarded as different traits. Holistic status of other unspecific and unidentified genes was estimated by using the statistical methods. Coefficients of kurtosis and skewness showed that the litter size still presented segregating characteristic in the 2nd, 5th, 7th, 8th and 9th parities. Analysis of homogeneity of variance between families confirmed the results for the 5th, 7th and 8th parities. The heritability of litter size for the 1st to 10th parities was estimated with paternal half-sib model and individual estimated breeding values (EBVs) were evaluated by a single trait animal model as well. We found that the averages of EBVs for litter size in each parity did not differ significantly between genotypes, despite the significant difference for original phenotype records in the 3rd, 4th and 5th parities (p<0.05 or p<0.01). The results may be explained by the deduction that the polymorphisms of ESR locus are no longer the important genetic base of litter size variation when the frequency of allele B accumulated in the experience of selection procedure, and further conferring that there exist special genes associated with litter size in the recent Tongcheng pigs population can be made. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 5 : 598-602)

Genetic variation of 27 microsatellite loci in three Hubei indigenous pig breeds

Genetic variability within and among three indigenous pig breeds (Tongcheng Pig, Qingping Pig and Yangxin Pig) in Hubei Province was surveyed, by means of 27 microsatellite loci recommended by ISAG (the International Society for Animal Genetics) and FAO(Food and Agriculture Organization). Genetic heterozygosity of each pig breed, polymorphism information content of each microsatellite locus and genetic distances among these populations were calculated. The results showed that allelic number and frequencies at the same locus obviously differed among the breeds. Some alleles were shared by all breeds, for instance 159bp, 162bp and 164bp in S0155, and 110bp in Sw72, while some other alleles were observed only in a single breed, such as 94bp and 96bp in Sw72 that were found solely in Yangxin Pig, 233bp, 245bp and 249bp in S0288 were in Tongcheng Pig, 249bp and 253bp in Sw90 were in Qingping Pig. Therefore, the common alleles (such as 158bp, 162bp and 164bp in S0155) are likely to be the oldest and the most distinctive for the native pig breeds of China. Geneic heterozygosity of three pig breed is 0.7489, 0.6987 and 0.6273 respectively, indication high genetic diversity. Genetic relationship between Tongcheng Pig and Qingping Pig is closer than their relationship with Yangxin Pig.