Expression Profiles of <Emphasis Type="Italic">IGF</Emphasis>-<Emphasis Type="Italic">1R</Emphasis> Gene and Polymorphisms of its Regulatory Regions in Different Pig Breeds

Insulin like growth factor 1 receptor (IGF-1R) is a candidate gene for growth and carcass traits in regulating animal growth, metabolism and endocrine. It is widely expressed in liver, muscle, bone tissues where the IGF-1R functions as a factor that promotes cell growth. In this study, the protein expression level of IGF-1R gene in liver and muscle tissues of three periods (birth, weaning and adult) of three pig breeds (BamaXiang pigs (BM), Tibetan pigs (TM) and Junmu No.1 pigs (JM)) were tested by western blot. SNPs within the regulatory region of pig IGF-1R gene were detected using direct sequencing and then the genotypes were identified through AS-PCR approach. Results showed expression profiles of IGF-1R gene between liver and muscle tissues were different and significant differences were also found among pig breeds. In the same time, four SNPs were detected in the regulatory region of IGF-1R gene, among which the genotype frequency of three (g.?1468G > C, g.?1192 C > T and g.330,424 C > T) were significantly different among the pig breeds. BM tended to heterozygous (GC/CT) of the anterior two loci, while TM and JM preferred the other two homozygotes respectively. For the g.330,424 C > T, all pig breeds were tended to be the heterozygous. In conclusion, the SNPs with different genotype distribution among the three pig breeds may explain the gene expression difference between the different pig breeds.     

Effect of <Emphasis Type="Italic">UCP2</Emphasis> and <Emphasis Type="Italic">UCP3</Emphasis> Genes Polymorphisms on Functional Traits in Dairy Cattle

The aim of this study was to investigate associations between genotypes of UCP2 and UCP3 genes, milk, and reproduction traits in dairy cattle. The study included two herds: Jersey cows and Polish Holstein-Friesian (Red and White strain) cows. All cows were genotyped using the PCR-RFLP method and allele frequencies were determined. Statistical analysis showed a significant association between polymorphism in the UCP3 gene and the milk yield and fat content of milk (P ≤ 0.05, P ≤ 0.01) and between the UCP2 gene and the calving interval (P ≤ 0.05). Information contained in this study may be useful in further analysis to define the role of analysed genes in relation to functional traits in dairy cattle, nevertheless, the obtained results should be verified by conducting research on a larger group of animals and various cattle breeds.     

Association of the <Emphasis Type="Italic">DGAT1</Emphasis> gene polymorphism in bulls with cow milk performance

The substitution of lysine for alanine (K232A) in the acyl-CoA:diacylglycerol acyltransferase, which is encoded by the DGAT1 gene, was tested for the significance for breeding evaluation of bulls of the holsteinized Black-and-White breed. The breeding value was estimated by the DYDC (daughter yield deviation to contemporaries) method with modification. The frequency of allele 232K in the bulls examined was 0.28, lower than in Holstein bulls (0.4–0.6). The greatest effect of the A232K substitution was observed for the percent fat milk yield (1.4σ) and milk yield (0.76σ), and a lower effect was established for the milk protein yield (0.47σ) and percent protein milk yield (0.44σ). In the case of milk fat yield, the effect was nonsignificant. A method was proposed for converting the data on fat yield in order to obtain significant results in this case as well. The effect of the A232K substitution was estimated at 154 kg for milk yield, 2.8 kg for milk protein yield, 0.079% for percent milk fat, and 0.015% for percent milk protein yield. The results are discussed in the context of multiple pleiotropic effects of the K232A substitution in the DGAT1 gene. It is proposed that the K232A substitution of the DGAT1 gene may be used as a golden standard in comparisons of the effect on milk production traits for the total gene set. This approach will allow a meta-analysis of the gene effects in spite of the different dairy cattle breeds and methods used to analyze their breeding value. In view of more than 30-year experience of using sperm of Holstein bulls, including those breeds in North America, it was noted that the effect of the A232K substitution on milk production traits agreed well with the data reported for the North American commercial population of Holstein cattle.     

Polymorphisms of DNA repair genes <Emphasis Type="Italic">ERCC</Emphasis>2 and <Emphasis Type="Italic">XRCC</Emphasis>1 in populations of Russia

We have conducted a comparative study of allele frequencies of single nucleotide polymorphisms (SNPs) rs1799793 and rs13181 of the ERCC2 gene as well as rs1799782 and rs25487 of the XRCC1 gene in population samples from European regions of Russia as well as in populations of Izhemski and Priluzski Komi and Yakuts. Significant differences in the distribution of polymorphic variants of the ERCC2 gene were demonstrated between populations of Yakuts and populations of Russians and Komi. In case of XRCC1 gene Izhemski Komi population exhibited dissimilar allele frequencies compared to other populations.     

Identification of three novel SNPs and association with carcass traits in porcine <Emphasis Type="Italic">TNNI1</Emphasis> and <Emphasis Type="Italic">TNNI2</Emphasis>

In this study, two novel SNPs (EU743939:g.5174T>C in intron 4 and EU743939:g.8350C>A in intron 7) in TNNI1 and one SNP (EU696779:g.1167C>T in intron 3) in TNNI2 were identified by PCR–RFLP (PCR restriction fragment length polymorphism) using XbaI, MspI and SmaI restriction enzyme, respectively. The allele frequencies of three novel SNPs were determined in the genetically diverse pig breeds including ten Chinese indigenous pigs and three Western commercial pig breeds. Association analysis of the SNPs with the carcass traits were conducted in a Large White × Meishan F₂ pig population. The linkage of two SNPs (g.5174T>C and g.8350C>A) in TNNI1 gene had significant effect on fat percentage. Besides these, the g.5174T>C polymorphism was also significantly associated with skin percentage (P < 0.05), shoulder fat thickness (P < 0.05) and backfat thickness between sixth and seventh ribs (P < 0.05). The significant effects of g.1167C>T polymorphism in TNNI2 gene on fat percentage (P < 0.01), lean meat percentage (P < 0.05), lion eye area (P < 0.05), thorax–waist backfat thickness (P < 0.01) and average backfat thickness (P < 0.05) were also found.     

Novel single nucleotide polymorphisms and haplotypes within the bovine<Emphasis Type="Italic"> CXCR2</Emphasis> gene

The objectives of this study were to identify single nucleotide polymorphisms (SNPs) and resulting haplotypes in the bovine CXCR2 gene. A 311-bp segment of the bovine CXCR2 gene was amplified and sequenced. Five SNPs at positions 612, 684, 777, 858, and 861 were expressed in both Holstein and Jersey dairy cattle. Four SNPs resulted in synonymous substitutions, while a non-synonymous switch at position 777 (GC) resulted in a glutamine to histidine substitution at amino acid residue 245. Strong linkage disequilibrium was exhibited for both breeds among all five loci (P<0.001). Both allele and genotype frequencies differed significantly with respect to breed at four of the five loci (P<0.001). The five polymorphisms generated ten distinct haplotypes. Six haplotypes were common between the two breeds, while Holsteins and Jerseys each uniquely expressed two haplotypes. Of the six common haplotypes, two represented 83% of the Jersey population; whereas four of these haplotypes represented 95% of the Holstein population.     

Polymorphism of <Emphasis Type="Italic">DLK1</Emphasis> and <Emphasis Type="Italic">CLPG</Emphasis> gene and their association with phenotypic traits in Chinese cattle

DLK1 and CLPG were located in DLK1-GTL2 imprinted cluster. They all affected muscle growth and meat tenderness. The functional importance of DLK1 and CLPG imply that the variation of the genes could affect the growth traits of animal. PCR-SSCP and sequencing were used to analyze the four loci of DLK1 gene and CLPG gene in 1109 individuals, which belong to eight breeds/species of bovidae, including cattle, buffalo and yak. A synonymous mutation (C451T) was detected in exon 5 of DLK1 in Qinchuan cattle, but didn’t change significantly with phenotypic traits. Three genotypes AA, AB and AC of CLPG were identified in Jiaxian cattle. The associations analyst of different genotypes showed that the individuals with genotypes AA and AC had a greater body weight and longer body length than those with genotype AB (P < 0.05 and P < 0.01, respectively); the AA individuals were different from those AB (P < 0.05) in the circumference of cannon bone. No polymorphism was observed in the other populations at other loci. These results were in agreement with the homology analysis: DLK1 and CLPG genes were in a highly conserved.     

Genetic association of <Emphasis Type="Italic">Phosphodiesterase 1B</Emphasis> (PDE1B) with carcass traits in Korean cattle

Quantitative trait loci for fat deposition and carcass traits have been identified in the vicinity of the gene encoding phosphodiesterase 1B (PDE1B) on bovine chromosome 5. Therefore, the PDE1B gene can be considered as a positional and functional candidate gene for carcass traits in beef cattle. This study aimed to identify single nucleotide polymorphisms (SNPs) in the PDE1B gene and to evaluate their associations with carcass traits in Korean cattle. Eight SNPs, g.440T>G, g.17122A>G, g.17507A>C, g.17575A>G, g.17607T>C, g.17609C>A, g.17692C>T, and g.17707C>G, were identified in the region ranged from exon 1 to intron 6. Five of them were used for association analysis because of their availability of restriction fragment length polymorphisms. As a result, g.17122A>G in intron 3 was significantly associated with backfat thickness (BFT), and g.17507A>C in exon 5 was associated with longissimus dorsi muscle area (LMA, P < 0.05). Animals with the AG genotype of g.17122 had thicker BFT than those with the AA genotype. Animals with the AA or AC genotype of g.17507A>C had larger LMA than those with the CC genotype. We suggested the PDE1B gene as a candidate gene for carcass traits of beef cattle. Fine mapping would be required for application to marker-assisted selection.     

Distribution of <Emphasis Type="Italic">BoLA-DRB3</Emphasis> allelic frequencies and identification of a new allele in the Iranian cattle breed Sistani (<Emphasis Type="Italic">Bos indicus</Emphasis>)

The distribution of the frequencies of BoLA-DRB3 gene alleles in the Iranian cattle breed Sistani was studied by the PCR-RFLP (“hemi-nested”) assay using restriction endonucleases RsaI, HaeIII and BstYI. In the examined cattle breed (65 animals) 32 alleles have been identified one of which being described for the first time (6.15% frequency). The nucleotide sequence of the polymorphic region of exon 2 of this allele has been determined and submitted in the GenBank database under accession number DQ486519. The submitted sequence has maximum homology (92%) with the previously described sequence DRB3-mRNA from Bos indicus (AccN X79346) and differs from it by 24 nucleotide substitutions which result in 16 amino acid substitutions. The peptide (on the basis of the reconstructed amino acid sequence) has 89% identity to the sequence encoded by the BIDRBF 188 locus (Bos indicus). The results obtained permit the sequence described by us to be considered as a new allele of the BoLA-DRB3 gene (DRB3.2 ^* X). The total frequency of the main six alleles (DRB3.2*8, *10, *11, *20, *34 and *X) occurring with a frequency of over 5% is about 60% in Iranian Sistani cattle. Fifteen alleles have <1% frequency. The highest frequency was observed for DRB3.2*8 allele (21.54%) like in other previously described breeds of Bos indicus (up to 23.07%). The Iranian breed Sistani has a high level of similarity by the spectrum of BoLA-DRB3 alleles and their frequencies to other Bos indicus breeds and significantly differs by these criteria from the Bos Taurus breeds. The Iranian Sistani herd under study includes alleles associated with to resistance to leukemia (DRB3.2*11 and *23) and to different forms of mastitis (DRB3.2* 2, *7, *11, *23 and *24) although their frequencies are low (from 0.77 to 5.37%). On the whole, a high level of diversity of BoLA-DRB3 gene alleles and the availability of alleles associated with resistance to different diseases makes this breed of interest for breeding practice. The article is published in the original.     

Identification and analysis of <Emphasis Type="Italic">MC4R</Emphasis> polymorphisms and their association with economic traits of Korean cattle (Hanwoo)

Signaling by the melanocortin-4 receptor (MC4R) is important for mediation the effect of leptin on food intake and energy homeostasis, and is associated with obesity, energy homeostasis and control of feeding behavior. Presently, the bovine MC4R gene was characterized to detect genetic variation at this locus and to relate it to economic traits in Korean cattle (Hanwoo). Five single nucleotide polymorphisms (SNPs) were identified in the coding region (G709A, C927T, C1069G, C1343A, and C1786T). G709A changed amino acid 166 of the MC4R protein from valine to methionine and C1069G changed amino acid 286 of the MC4R protein from leucine to valine. A SNP at C927T significantly influenced the Marbling score, SNP markers C1069G and C1343A significantly affected the Backfat thickness, and the SNP marker C1786T significantly influenced backfat and Marbling score. The MC4R gene may thus be a candidate gene for carcass traits with MC4R SNPs being potentially valuable as genetic markers for economic traits in Hanwoo.     

Molecular characterization and association analysis with production traits of the porcine <Emphasis Type="Italic">INPP5F</Emphasis> Gene

Inositol polyphosphate-5-phosphatase F (INPP5F) is one of the largest families of phosphoinositide phosphatases, 5-phosphatase. It contains a Sac domain whose amino acids are essential for inositol polyphosphate phosphatase activities. Here, we assigned the porcine INPP5F to SSC14q29 by using SCHP and IMpRH. Sequencing of PCR products from different breeds identified an A/G polymorphism in the last exon. The allele frequencies of this SNP showed that the Yorkshire and Duroc pigs have high G allele frequency, whereas the local pigs have high A allele frequency. Association analysis of the genotypes with growth and carcass traits found that different genotypes of INPP5F have significant differences in average daily gain (ADG) (P < 0.05) in Yorkshire pigs.     

mtDNA Diversity and genetic lineages of eighteen cattle breeds from <Emphasis Type="Italic">Bos taurus </Emphasis>and<Emphasis Type="Italic"> Bos indicus</Emphasis> in China

In order to clarify the origin and genetic diversity of indigenous cattle breeds in China, we carried out phylogenetic analysis of representatives of those breeds by employing mitochondrial gene polymorphism. Complete cyt b gene sequences, 1140 bp in length, were determined for a total of 136 individuals from 18 different breeds and these sequences were clustered into two distinct genetic lineages: taurine (Bos taurus) and zebu (Bos indicus). In analysis of the cyt b gene diversity, Chinese cattle showed higher nucleotide (0.00923) and haplotype diversity (0.848) than the reports from other studies, and the animals from the taurine lineage indicated higher nucleotide diversity (0.00330) and haplotype diversity (0.746) than the ones from the zebu lineage (0.00136; 0.661). The zebu mtDNA dominated in the southern breeds (63.3–100%), while the taurine dominated in the northern breeds (81.8–100%). Six cattle breeds from the central area of China exhibited intermediate frequencies of zebu mtDNA (25–71.4%). This polymorphism revealed a declining south-to-north gradient of female zebu introgression and a geographical hybrid zone of Bos taurus and Bos indicus in China.     

The porcine <Emphasis Type="Italic">TBC1D1</Emphasis> gene: mapping,SNP identification,and association study with meat,carcass and production traits in Italian heavy pigs

TBC1D1 [TBC1 (tre-2/USP6, BUB2, cdc16) domain family, member 1] is a Rab-GTPase-activating related protein implicated in regulating the trafficking of glucose transporter 4 (GLUT4 or SLC2A4) storage vesicles to the cell surface in response to insulin and AMPK-activating stimuli in skeletal muscle. Mutations in the human and mouse TBC1D1 genes confer risk of obesity or leanness. We identified five single nucleotide polymorphisms (SNPs) in the porcine TBC1D1 gene. One of them (FN677935:g.219G>A) was genotyped either by high resolution melting and PCR-RFLP analyses to study allele frequencies in a few pig breeds and evaluate association with meat production and carcass traits in five groups of sib-tested pigs of Italian Large White and Italian Duroc breeds. The g.219G>A SNP was associated (P < 0.05) with ham weight, back fat thickness and lean cuts content in Italian Large White and with visible intermuscular fat in Italian Duroc pigs.     

Polymorphism of intron 2 of the <Emphasis Type="Italic">SDF1</Emphasis> gene in Galloway,Hereford, and Russian Black Pied cattle

The region of intron 2 of the SDF1 gene encoding a chemokine of the CXC subfamily has been resequenced in Galloway, Hereford, and Black Pied cattle. Five of the single-nucleotide polymorphisms (SNP) that were earlier detected by other authors in various breeds of cattle in North America (99C/G, 128T/C, 206C/T, 267C/G and 313C/T) have been found. The 270insC polymorphic marker has proved to be monomorphic in Russian cattle breeds. Hereford cattle significantly differ from Galloway and Black Pied cattle in the frequencies of some SNP variants and their combinations. The number of SNP combinations in Hereford and Galloway cattle exceeds that in Black Pied cattle.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

Isolation,mapping, SNP detection and association with backfat traits of the porcine <Emphasis Type="Italic">CTNNBL1</Emphasis> and <Emphasis Type="Italic">DGAT2</Emphasis> genes

Both the CTNNBL1 (catenin, β-like1) and DGAT2 (diacylglycerol acyltransferase2) genes play important roles in adipose metabolism. In this study, we cloned these two genes in pigs. Semi-quantitative RT-PCR results showed that both genes were extensively expressed, and CTNNBL1 was at a high level in the heart and spleen, while DGAT2 was most abundant in the liver. In CTNNBL1, one synonymous mutation c.555C>T was identified in the coding region, and association analysis showed that different genotypes of CTNNBL1 were significantly associated with backfat at the shoulder and backfat at the rump (P < 0.05). In 3′-UTR of DGAT2, an A/G variation was detected by the Bcn I PCR-RFLP method, and different genotypes were significantly associated with backfat between the 6th and 7th ribs (P < 0.05). The allele frequency was tested among 188 unrelated pigs from six breeds. The results showed that for CTNNBL1, the Chinese indigenous breeds had higher frequencies of the C allele whereas the western breed had higher frequency of the T allele; and for DGAT2, allele A or G were distributed with no obvious difference in allele frequency. IMpRH was employed to localize these two genes, and CTNNBL1 was assigned to SSC17q21-23 and DGAT2 was assigned to SSC9p23-p24. The results suggest that the porcine CTNNBL1 and DGAT2 genes affect porcine fat deposition and further investigation will be necessary to illustrate the underlying mechanisms.     

Polymorphism of the <Emphasis Type="Italic">BoLA-DRB3</Emphasis> gene in the Mongolian,Kalmyk, and Yakut cattle breeds

Polymorphism of the BoLA-DRB3 gene was studied with the use of the PCR-RFLP technique in three cattle breeds (Mongolian, Kalmyk, and Yakut) representing the Bos taurus turano-mongolicus group. 35 BoLA-DRB3.2 alleles were detected in the Mongolian breed and 34 alleles in the Kalmyk breed. The frequencies of alleles in both populations are distributed rather evenly: the frequencies of the most widely represented alleles (*18, *20, and *28) in the Mongolian cattle varied from 7.75 to 8.45%. The most frequent alleles in the Kalmyk cattle were *28 (14.52%), *24 (7.26%), and *12 (6.45%). Only five alleles were identified in the Yakut cattle breed. The prevailing allele was *29 (77.3%); a relatively frequent allele was *1 (13.1%), and the remaining three alleles constituted only 9.6%. Such a low level of diversity of BoLA-DRB3 gene alleles was not observed earlier in any other cattle breed. The Mongolian and Kalmyk breeds showed a wide diversity of BoLA-DRB3 genotypes (56 and 51 genotypes, respectively) and a high level of expected heterozygosity (H _e = 0.953 and 0.946, respectively). Both breeds had a deficiency of heterozygotes (Mongolian cattle: H _o = 0.775, D = −0.187; Kalmyk cattle: H _o = 0.708, D = −0.252). A low level of genotypic diversity for the BoLA-DRB3 locus (only seven genotypes; the frequency for the genotype *29/*29 is 71.4%) and a very low level of observed heterozygosity (H _o = 0.12) were revealed in the Yakut breed. BoLA-DRB3.2 alleles associated with resistance to persistent lymphocytosis caused by the bovine leukemia virus (total frequencies 15.49 and 24.19%) and to various forms of mastitis (total frequencies 12.68 and 20.96%, respectively) were identified in the Mongolian and Kalmyk animals. In the Yakut breed, alleles associated with resistance to diseases are represented only by the BoLA-DRB3.2 allele *7 (1.2%). Thus, the Mongolian and Kalmyk cattle breeds are characterized by a wide diversity of alleles and genotypes for the BoLA-DRB3 gene. In contrast, the population of Yakut cattle from the Verkhoyanskii region of the Republic of Sakha has a poor diversity of alleles and genotypes for the BoLA-DRB3 gene and a very low level of heterozygosity, suggesting an unfavorable state of the population that is probably caused by inbreeding depression due to a long-term isolation and a small number of animals.     

Polymorphism of the prion protein gene (<Emphasis Type="Italic">PRNP</Emphasis>) in two Chinese indigenous cattle breeds

Prion protein (PRNP) gene has been located at position q17 of chromosome 13 in cattle. The polymorphisms of PRNP gene might be associated with BSE susceptibility. In the present work, we investigated the polymorphisms of PRNP gene, including SNP in exon 3, 23-bp indel in promoter region, 12-bp indel in intron 1 in 2 Chinese indigenous cattle breeds of northeast China. Eighty-six animals from Yanbian (34) and Chinese Red Steppes (52) were genotyped at PRNP locus by analyzing genomic DNA. A total of 4 single nucleotide polymorphism (SNP) sites were revealed in the PRNP gene exon 3 of the 2 cattle breeds investigated. Three of these SNPs were non-synonymous mutations that resulted in the amino acid exchanges (K119N, S154N, and M177V), and one is silent nucleotide substitutions (A234G). The two amino acid mutations of S154N and M177V were detected only in Yanbian with a very low frequency (0.0147), and they appears to be absent in Chinese Red Steppes. The average gene heterozygosity (H _e), effective allele numbers (N _e), Shannon’s information index (I) and polymorphism information content (PIC) were 0.3088, 1.5013, 0.3814 and 0.2000 in Yanbian, respectively, being relatively higher than that of Chinese Red Steppes (0.2885, 1.4985, 0.3462 and 0.1873, respectively). In 23-bp indel and 12-bp indel loci, three different genotypes were identified in both Yanbian and Chinese Red Steppes breeds. Based 23- and 12-bp indels, four haplotypes was constructed in the 2 Chinese cattle breeds, of which the 23-bp (−)/12-bp (−) was main haplotypes accounting for more than 50% of the total in both Yanbian and Chinese Red Steppes breeds. These results might be useful in understanding the genetic characteristics of PRNP gene in Chinese indigenous cattle breeds.