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This study characterized autochthonous pig breeds of Vietnam and compared them with breeds from other regions. A total of 343 animals were considered from 5 indigenous pig breeds of Vietnam (Muong Khuong, Co, Meo, Tap Na, and Mong Cai), 2 exotic breeds kept in Vietnam (Landrace and Yorkshire), 3 European commercial breeds (German Landrace, Piétrain, and Large White), the Chinese breed Meishan, and the European Wild Boar. Each individual was genotyped for 20 selected polymorphic microsatellite loci. The Vietnamese autochthonous breeds showed higher degrees of polymorphism, allelic diversity, and heterozygosity than the other pig breeds. Also, large genetic diversity was observed across the area of distribution, with village-specific subpopulations, which led to significant inbreeding coefficients. As expected, genetic distances showed large differences among European-based, Chinese, and Vietnamese indigenous breeds and reflected the geographical distribution of breeds. In comparison with the European breeds, the Vietnamese indigenous pig breeds harbored a considerable amount of genetic diversity and, therefore, will be of significance for livestock bioconservation. [ABSTRACT FROM AUTHOR]

The lamins are components of nuclear lamina and they have a profound influence on nuclear structure and functions. They are encoded by three genes, LMNA, LMNB1 and LMNB2. A genomic fragment of the porcine LMNA gene (822 bp; from exons 7 to 9) was amplified by polymerase chain reaction and comparatively sequenced. Four single nucleotide polymorphisms (SNPs) were identified in intronic sequences: G162 A, G208 A, T367 G and C618 T. The SNPs are within the restriction sites for enzymes Bsh1236I, HpaII, AluI and Bsh1236I respectively. Allele frequencies at SNPs G208 A, T367 G and C618 T were determined by using eight pig breeds. Linkage analysis in the Hohenheim Meishan × Piétrain family placed the LMNA gene in the chromosome 4q linkage group, between MEF2D and GBA ( MEF2D– 3.0 cM – LMNA– 0.2 cM – GBA). In radiation hybrid mapping LMNA was most significantly linked to SW270 on chromosome 4 (39 cR; LOD = 7.86). The LMNA gene is located in the quantitative trait loci region for some carcass traits on chromosome 4q. [ABSTRACT FROM AUTHOR]

Polymorphic microsatellite and open-reading frame (ORF) sites in the prion protein coding gene (PRNP) were analysed in eight sheep breeds. The three microsatellite sitesS11,S15andS24were genotyped by fragment length analysis, and the ORF codons 136, 154 and 171 were analysed after direct sequencing. Unexpected polymerase chain reaction (PCR) products of microsatellite sites and ORF haplotypes with more than one heterozygous site were submitted to cloning and then sequenced. The microsatellite sites were polymorphic in all breeds with two to five alleles per site. On average of breeds and sites, the microsatellites had higher degrees of polymorphism than the ORF sites. TheARR/ARRORF genotype occurred always together with the microsatellite genotypesS11152/152,S15179/179 andS24144/144. As ORF and microsatellite alleles of thePRNPwere observed in typical combinations, the microsatellite genotypes were significantly associated with scrapie incidences or risk classes based on the ORF genotypes. The microsatellite sites were highly polymorphic and therefore are advantageous markers for evaluation of scrapie disposition and fine mapping of effects on scrapie pathogenesis within the gene. [ABSTRACT FROM AUTHOR]

Linkage maps of Sus scrofa chromosome 5 (SSC5) were constructed using up to 10 markers in three informative F2 families based on Wild Boar (W), Meishan (M) and Pietrain (P) crosses. The map lengths differed among the families. In the M × P family, the MYF5 locus was linkage mapped between SW995 and SW967. Relatively few quantitative trait loci (QTLs) were observed on SSC5 explaining a maximum of 5.8% of phenotypic variance in the F2 generation. The presence and position of QTLs were not consistent among families. The Meishan and Wild Boar QTL allele effects were inferior compared with Pietrain allele effects. The additive effects were small and reasonably strong dominance-effects were observed. QTLs affecting conductivity in the W × M family and food conversion ratio in the M x P family mapped near MYF5, while the QTL affecting conductivity in the M x P family was located near IGF1. [ABSTRACT FROM AUTHOR]

Linkage maps have been constructed for Sus scrofa chromosome 6 (SSC6) based on 17 markers, of which 10 were used in all three F2 families of Wild Boar (W), Meishan (M) and Pietrain (P) crosses. The coverage of the linkage maps of SSC6 was almost complete. All loci were ordered identically in the families, but two intervals (RYR1-A1BG-EAH, S0146-S0003-SW824) differed from published maps. Major quantitative trait loci (QTLs) for meat quality, stress resistance and carcass composition explaining up to 59% of F2 phenotypic variance have been mapped in the M x P and W x P families centred on the segregating R YR1 T and C alleles. In the W × M family, which was homozygous for the RYR1 C allele, no QTL effects for meat quality and stress-resistance, but moderate effects for carcass composition have been observed in this region. These findings indicate further loci closely linked with the RYR1 or/and further alleles at the RYR1 locus, involved in the variation of carcass and growth traits. [ABSTRACT FROM AUTHOR]

Linkage maps of Sus scrofa chromosome 4 (SSC4) based on 19 markers were similar in lengths for three F2-families [Wild Boar (W), Meishan (M) and Pietrain (P) crosses] and in agreement with the previously published maps. Quantitative trait loci (QTLs) on SSC4 affect mainly muscle and fat mass. Compared with others, Pietrain alleles were associated with longer carcass, higher body weight and higher meat content. In all three families, the profiles of F ratio values for these traits showed peaks close to the positions of candidate genes V-ATPase, ATP1A2 and ATP1B1. Additional more proximally mapped QTLs, significant at the p < 0.05 chromosome-wide level, were found in the M x P and W x P families. The W × M family revealed highly significant QTLs located in the vicinity of AMPD1 and NGFB. The SSC4 QTLs explained up to 12% of F2 phenotypic variance. [ABSTRACT FROM AUTHOR]

Sus scrofa chromosome 2 (SSC2) linkage maps were generated from three F2 families involving Meishan (M), Pietrain (P) and Wild Boar (W) crosses and the same 10 marker loci. SSC2 linkage maps were similar between families and correspond to published maps. Quantitative trait loci (QTLs) for carcass traits, daily gain and heart weight were identified on SSC2, especially in the intervals 0-20 and 80-90 cM in the M × P family, the intervals 20-50 and 125-140 cM in the W × P family, and the interval 15-70 cM in the W × M family. QTL presence and position varied among families. QTL effects explained up to 10% of F2 phenotypic variance. Pietrain QTL alleles were associated with high muscle and heart mass, high daily gain and low fat deposition and Meishan alleles with high carcass fat content. Wild Boar alleles were associated with leaner carcass but lower daily gain than Meishan alleles. [ABSTRACT FROM AUTHOR]

Linkage maps of Sus scrofa chromosome 1 (SSC1) have been produced using 10 markers in three different F2 families based on crosses of Meishan (M), Pietrain (P) and Wild Boar (W). The maps were similar for the different families and show higher paternal recombination, especially in the interval SW2130-SW803. Quantitative trait loci (QTLs) affecting body conformation, carcass composition, fat deposition and numbers of teats were identified in all three families. Major QTLs were mapped in chromosomal intervals centred at approximately 60, 120 and 170 cM. The QTLs explain up to 8.4% of phenotypic variance in the F2 generation. Pietrain QTL alleles were superior in comparison with Wild Boar andMeishan alleles for most of the trait values. Meishan alleles were associated with highest fat deposition. Additive gene effects were generally larger than dominance effects. QTL profiles on SSC1 differed between families, with the W x P family being most distinct. [ABSTRACT FROM AUTHOR]