• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.939-945
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• 2003

Seventeen Chinese indigenous pig breeds and three introduced pig breeds had been carried out by means of vertical polyacrylamide gel electrophoresis (PAGE). According to the results, eight serum protein loci were highly polymorphic except Pi-2 and Cp. The polymorphism information content (PIC) of Hpx was the highest (0.5268), while that of Cp was the lowest (0.0257). The population genetic variation index showed that about 84% genetic variation existed in the population, and the rest of 16% distributed between the populations. The genetic variation of Yimeng black pig and Duroc were the highest and the lowest, respectively. The genetic variation of Chinese indigenous pig breeds was much more than that of exotic groups. Genetic distance results showed that Chinese indigenous pig breeds were classified into four groups with the three introduced pig breeds clustered into another group. The results also supported the geographic distribution of Chinese indigenous pig breeds in certain extent.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.441-444
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• 2004

The genetic diversities and relationships of 10 Chinese indigenous pig breeds and three exotic pig breeds have been evaluated using 26 microsatellites recommended by the Food and Agriculture Organization & the International Society of Animal Genetics (FAO-ISAG). The allele frequencies, genetic heterozygosity (H) and polymorphism information content (PIC) have been calculated. The results showed that genetic diversity of Chinese indigenous pig breeds is higher than that of the introduced pig breeds. The clustering of 10 breeds is generally consistent with their geographical distribution.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1193-1195
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• 2000

The polymorphisms of six microsatellites were investigated in four indigenous pig breeds (Erhualian, Tongcheng, Qingping and Wannanhua) and three introduced breeds (Large White, Landrace and Duroc) in China, and the genetic variations within and among populations were analyzed. The results showed that genetic diversity of Chinese indigenous pig breeds is higher than that of the introduced pig breeds. The clustering of seven breeds is consistent with their geographical distribution approximately. Estimated time of breed divergence ranged from 653 to 1856 years.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.28-36
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• 2011

To investigate the genetic diversity of six Chinese indigenous pig breeds in Shandong province (Laiwu Black, Dapulian Black, Licha Black, Yantai Black, Yimeng Black and Wulian Black), explain their genetic relationship and assess their integrity and degree of admixture with three Western commercial breeds (Landrace, Yorkshire and Duroc), 303 individuals from these breeds were genotyped for 26 microsatellite markers. In general, high genetic diversity (observed heterozygosity ranging from 0.5495 to 0.7746) and large breed differentiation ($F_{ST}$ = 0.188) were observed. The indigenous pig breeds in Shandong exhibited consistently higher levels of genetic diversity than the three Western breeds. However, compared with the Western breeds, which have an $F_{ST}$ value of 0.252, the indigenous breeds in Shandong have smaller $F_{ST}$ value of 0.145. The analysis of breed relationship indicated that the six indigenous breeds are classified into two groups. One includes four breeds, Licha, Yantai, Yimeng and Wulian, which have experienced large gene introgression of the Western breeds through progressive crossbreeding as well as gene flow among themselves. The other includes Laiwu and Dapulian, which are less influenced by the Western breeds and other indigenous breeds in Shandong in the recent past. The results show that some measures must be taken to effectively protect these indigenous pig breeds in Shandong.

• Animal Bioscience
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• v.34 no.7
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• pp.1123-1133
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• 2021

Objective: Shandong indigenous pig breeds are important Chinese pig resources. Their progressive population decline in recent decades has attracted attention towards their conservation. Conservation genetics of these indigenous breeds are essential for developing a conservation and utilization scheme. Methods: A high-density single nucleotide polymorphism (HD-SNP) chip-based comparative analysis of genetic characteristics was performed for seven Shandong indigenous pig breeds in the context of five Western commercial breeds. Results: The results showed that Shandong indigenous pig breeds varied greatly in genetic diversity, effective population size, inbreeding level, and genetic distance with the Western commercial breeds. Specifically, Laiwu and Dapulian displayed low genetic diversity, and had a genetically distant relationship with the Western commercial breeds (average F statistics [F_ST] value of 0.3226 and 0.2666, respectively). Contrastingly, the other five breeds (Yantai, Licha, Yimeng, Wulain, and Heigai) displayed high genetic diversity within breed and had some extent of mixture pattern with the Western commercial breeds, especially Duroc and Landrace (F_ST values from 0.1043 to 0.2536). Furthermore, intensive gene flow was discovered among the seven Shandong indigenous breeds, particularly Wulian, Licha, and Heigai, as indicated by the large cluster formed in the principal component analysis scatterplot and small population differentiation (average of 0.1253) among them. Conclusion: Our study advances the understanding of genetic characteristics of Shandong indigenous breeds and provides essential information for developing an appropriate conservation and utilization scheme for these breeds.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.212-218
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• 2020

Objective: Agu pigs are indigenous to the Okinawa prefecture, which is the southernmost region of Japan. Agu pigs were exposed to a genetic bottleneck during the 20th century, due to the introduction of European pig breeds. The objective of this study was to elucidate the genetic structure of Agu pigs and to determine their relationships with those of five European breeds, two Chinese breeds and Ryukyu wild boar using microsatellite markers. Methods: A total of 203 DNA samples from 8 pig breeds were used in this study. Genotyping was performed using 21 microsatellite markers distributed across 17 chromosomes. Results: Numbers of effective alleles in Agu pigs were fewer than in European breeds and Ryukyu wild boar. Among domestic pigs, Agu pigs had the lowest heterozygosity (0.423) and highest inbreeding coefficient (F_IS = 0.202), indicating a severe loss of heterozygosity in Agu pigs possibly due to inbreeding. Neighbor-joining tree analysis was performed based on Reynolds' genetic distances, which clustered Agu pigs with Duroc pigs. However, principal component analysis revealed a unique genetic position of the Agu pig, and the second principal component separated Agu pigs from all other breeds. Structure analysis with the optimal assumption of seven groups (K = 7) indicated that Agu pigs form an independent cluster from the other breeds. In addition, high and significant F_ST values (0.235 to 0.413) were identified between Agu pigs and the other breeds. Conclusion: This study revealed a substantial loss of genetic diversity among Agu pigs due to inbreeding. Our data also suggest that Agu pigs have a distinctive genetic structure, although gene flows from European breeds were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1491-1500
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• 2019

Objective: European pigs have been imported to improve the economically important traits of Thai pigs by crossbreeding and was finally completely replaced. Currently Thai indigenous pigs are particularly kept in a small population. Therefore, indigenous pigs risk losing their genetic diversity and identity. Thus, this study was conducted to perform large-scale genetic diversity and phylogenetic analyses on the many pig breeds available in Thailand. Methods: Genetic diversity and phylogenetics analyses of 222 pigs belonging to Thai native pigs (TNP), Thai wild boars (TWB), European commercial pigs, commercial crossbred pigs, and Chinese indigenous pigs were investigated by genotyping using 26 microsatellite markers. Results: The results showed that Thai pig populations had a high genetic diversity with mean total and effective ($N_e$) number of alleles of 14.59 and 3.71, respectively, and expected heterozygosity ($H_e$) across loci (0.710). The polymorphic information content per locus ranged between 0.651 and 0.914 leading to an average value above all loci of 0.789, and private alleles were found in six populations. The higher $H_e$ compared to observed heterozygosity ($H_o$) in TNP, TWB, and the commercial pigs indicated some inbreeding within a population. The Nei's genetic distance, mean $F_{ST}$ estimates, neighbour-joining tree of populations and individual, as well as multidimensional analysis indicated close genetic relationship between Thai indigenous pigs and some Chinese pigs, and they are distinctly different from European pigs. Conclusion: Our study reveals a close genetic relationship between TNP and Chinese pigs. The genetic introgression from European breeds is found in some TNP populations, and signs of genetic erosion are shown. Private alleles found in this study should be taken into consideration for the breeding program. The genetic information from this study will be a benefit for both conservation and utilization of Thai pig genetic resources.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1219-1222
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• 2004

The genetic diversities of 10 Chinese pig populations were analyzed by using microsatellite DNA polymorphisms. The results showed that the mean heterozygosities of the 10 populations were between 0.4561 and 0.6446, the mean polymorphism information contents were 0.4241-0.6184 and the mean effective number of alleles were 2.4295-3.7573. These indicated that the genetic diversity of local Chinese pigs was high. The clustering of the 10 populations was nearly inaccordance with their geographical distributions.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.930-937
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• 2017

Objective: The I pig is a long nurtured longstanding breed in Vietnam, and contains excellent indigenous genetic resources. However, after 1970s, I pig breeds have become a small population because of decreasing farming areas and increasing pressure from foreign breeds with a high growth rate. Thus, there is now the risk of the disappearance of the I pigs breed. The aim of this study was to focus on classifying and identifying the I pig genetic origin and supplying molecular makers for conservation activities. Methods: This study sequenced the complete mitochondrial genome and used the sequencing result to analyze the phylogenetic relationship of I pig with Asian and European domestic pigs and wild boars. The full sequence was annotated and predicted the secondary tRNA. Results: The total length of I pig mitochondrial genome (accession number KX094894) was 16,731 base pairs, comprised two rRNA (12S and 16S), 22 tRNA and 13 mRNA genes. The annotation structures were not different from other pig breeds. Some component indexes as AT content, GC, and AT skew were counted, in which AT content (60.09%) was smaller than other pigs. We built the phylogenetic trees from full sequence and D loop sequence using Bayesian method. The result showed that I pig, Banna mini, wild boar (WB) Vietnam and WB Hainan or WB Korea, WB Japan were a cluster. They were a group within the Asian clade distinct from Chinese pigs and other Asian breeds in both phylogenetic trees (0.0004 and 0.0057, respectively). Conclusion: These results were similar to previous phylogenic study in Vietnamese pig and showed the genetic distinctness of I pig with other Asian domestic pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1183-1187
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• 2004

The natural resistance-associated macrophage protein 1 (NRAMP1) gene was identified as a candidate gene controlling the resistance and susceptibility to a number of intracellular parasites in pigs. The genetic variations in a 1.6 kb region spanning exon 1 and exon 3 of the porcine NRAMP1 gene were investigated by PCR-HinfI-RFLP in samples of 1347 individuals from 21 Chinese indigenous pig populations and 3 western pig breeds. Three alleles (A, B, C) and four genotypes (AA, BB, AB, BC) were detected. Significant differences in genotype and allele frequencies were observed between Chinese indigenous pig populations and exotic pig breeds, while in general the differences in genotype and allele frequencies among Chinese indigenous pig populations were not significant. The allele C was detected only in Duroc, Leping Spotted and Dongxiang Spotted pig, and the two Chinese pig populations showed similar genotype and allele frequencies. Four Chinese Tibetan pig populations displayed genetic differentiation at the NRAMP1 gene locus. In addition, intron 5 of the NRAMP1 gene was isolated and characterized by directly sequencing the PCR products encompassing intron 5. The alignment of intron 5 of the porcine, human, equine and ovine NRAMP1 gene showed a similarity of 45.38% between pig and human, 52.55% between pig and horse, 63.47% between pig and sheep, respectively.