• Journal of Animal Science and Technology
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• v.57 no.3
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• pp.12.1-12.5
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• 2015

Background: The Korean native pig (KNP) is generally thought to have come from northern China to the Korean peninsula approximately 2000 years ago. KNP pigs were at the brink of extinction in the 1980s, since then efforts have been made to restore the breed by bringing together the remaining stocks in South Korea. As a result, KNP was registered as a breed in 2006. To find additional breed-specific markers that are distinct among pig breeds, variations in O-linked N-acetylglucosamine transferase (OGT) were investigated. OGT is located on chromosome X and catalyzes the post-translational addition of a single O-linked-${\beta}$-N-acetylglucosamine to target proteins. Findings: Length polymorphism in the intron 20 of OGT was identified. The intron 20 of OGT from Duroc, Landrace, and Yorkshire breeds was 281-bp longer than that from either KNP or Chinese Meishan pigs. The difference between the Western pig breeds (BB genotype) and KNP or Meishan pigs (AA genotype) was due to an inserted 276-bp element and the 5-bp ACTTG. Conclusions: The polymorphism in OGT identified in this study may be used as an additional marker for determining the breed of origin among Meishan and the Western pig breeds. The length polymorphism suggests that the locus near OGT is not fixed in KNP. This marker would be relevant in determining the breed of origin in crossbred pigs between KNP pigs with known genotypes and the Western pig breeds with BB genotypes, thus confirming the contribution of the X chromosome from each breed.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.403-409
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• 2010

Accurate methods for the identification of closely related species or breeds in raw and processed meats must be developed in order to protect both consumers and producers from mislabeling and fraud. This paper describes the development of DNA markers for the discrimination and improvement of Korean native pig (KNP) meat. The KIT gene is related to pig coat color and is often used as a candidate marker. A 538 bp fragment comprising intron 19 of the pig KIT gene was amplified by PCR using specific primers, after which the PCR amplicons of a number of meat samples from KNP and three major improved breeds (Landrace, Duroc and Yorkshire) were sequenced in order to find a nucleotide region suitable for PCR-RFLP analysis. Sequence data showed the presence of two nucleotide substitutions, g.276G>A and g.295A>C, between KNP and the improved pig breeds. Digestion of KIT amplicons with AccII enzyme generated characteristic PCR-RFLP profiles that allowed discrimination between meats from KNP and improved pig. KNP showed three visible DNA bands of 264/249, 199, and 75 bp, whereas DNA bands of 249, 199, and 90 bp were detected in the three improved pig breeds. Therefore, the 75 bp DNA fragment was specific only to KNP, whereas the 90 bp DNA fragment was specific to the improved breeds. The breed-specific DNA markers reported here that target the KIT gene could be useful for the identification of KNP meat from improved pig meats, thus contributing to the prevention of falsified breed labeling.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.485-493
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• 2019

Objective: This study was undertaken to investigate the genetic characteristics of Berkshire (BS), Landrace (LR), and Yorkshire (YS) pig breeds raised in the Great Grandparents pig farms using the single nucleotide polymorphisms (SNP) information. Methods: A total of 25,921 common SNP genotype markers in three pig breeds were used to estimate the expected heterozygosity ($H_E$), polymorphism information content, F-statistics ($F_{ST}$), linkage disequilibrium (LD) and effective population size ($N_e$). Results: The chromosome-wise distribution of $F_{ST}$ in BS, LR, and YS populations were within the range of 0-0.36, and the average $F_{ST}$ value was estimated to be $0.07{\pm}0.06$. This result indicated some level of genetic segregation. An average LD ($r^2$) for the BS, LR, and YS breeds was estimated to be approximately 0.41. This study also found an average $N_e$ of 19.9 (BS), 31.4 (LR), and 34.1 (YS) over the last 5th generations. The effective population size for the BS, LR, and YS breeds decreased at a consistent rate from 50th to 10th generations ago. With a relatively faster $N_e$ decline rate in the past 10th generations, there exists possible evidence for intensive selection practices in pigs in the recent past. Conclusion: To develop customized chips for the genomic selection of various breeds, it is important to select and utilize SNP based on the genetic characteristics of each breed. Since the improvement efficiency of breed pigs increases sharply by the population size, it is important to increase test units for the improvement and it is desirable to establish the pig improvement network system to expand the unit of breed pig improvement through the genetic connection among breed pig farms.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.405-414
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• 2007

Pigs have been considered as an ideal source of donor organs because of their plentiful supply and their numerous anatomical and physiological similarities to the human in xenotransplantation. However, for the public health risks associated with the potential for porcine endogenous retrovirus(PERV) infection through xenograft from pig to human, the investigation of methods for elimination and/or control of PERV has been required. In this study we developed the detection and classification methods for PERV based on PCR using specific primers. PERV-A and PERV-B were found in all pigs including Berkshire, Duroc, Landrace, Yorkshire, miniature pig, and Korean native black pig from Jeju by PCR with type-specific primers for PERV. However, PERV-C was detected only from Duroc, miniature pig, and Korean native black pig from Jeju. PERV-A and PERV-B could be distinguished by PCR-RFLP with BamHI. These methods for PERV will be useful in rapid screening of safe organ for xenograft, furthermore, helpful in monitoring of PERV during and after xenotransplantation.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.595-602
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• 2016

In pigs, individuals in the same pen may show aggressive behavior toward each other, such as tail biting. Such social interactions among pen mates may considerably affect their welfare and performance, both in negative and positive ways. The present study was conducted to investigate social genetic effects on days to 90 kg using data from 12,208 Duroc and Yorkshire pigs that were born between 2008 and 2012. Heritability was estimated using the five following animal models: a basic model with direct heritable effects only (Model 1), a social model with direct and social heritable effects (Model 2), a model accounting for covariance between direct and social heritable effects (Model 3), and two models considering a dilution factor with direct and social heritable effects (Models 4 and 5). The optimal model to represent Duroc pigs was Model 1 which only uses direct heritable effects. Direct heritability (0.21) was higher than total heritability (0.09) and covariance was negative. Model 2 was evaluated as the optimum model for Yorkshire pigs. Yorkshire data showed that total heritability (0.5) was twice as high as direct heritability (0.25) and covariance was positive. Our results suggest that the efficiency of social effects differed among breeding lines. Further research on social effects related to breeds by group size would clarify which is the most efficient selection method that accounts for social genetic effects.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.523-528
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• 2003

This study was performed to investigate a possible association of the porcine estrogen receptor(ER) locus with the total number of born(TNB) and number of born alive(NBA) in Yorkshire pigs. Using DNAs extracted from 242 Yorkshire pigs, the ER genotype was determined by PvuII PCR-RFLP. The ER allele frequencies of two types of A and B were 0.39 and 0.61, respectively. The least squares means of the litter size by ER genotype was evaluated. The TNB and NBA were found to be associated with an specific ER allele. The genotype at the porcine ER locus has an application potential for marker-assisted selection for litter size in pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.922-925
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• 2015

This study was conducted to estimate the genetic parameters for pork belly traits and muscles in Yorkshire pigs. Each pork belly was cut into nine parts perpendicular to the thoracic vertebrae (6th to 14th). Traits of belly muscles including the deep pectoral, latissimus dorsi, cutaneous trunci, rectus abdominis, external and internal abdominal oblique from 382 purebred pigs were recorded and analyzed using SAS Package (9.1) and Derivative-free restricted maximum likelihood methods. Heritability estimates for belly traits ranged from 0.27 to 0.49, while they were 0.12 to 0.66 for belly muscles. Moderate to high heritability estimates were noted in belly weight (0.33), belly length (0.28), and belly width (0.49). In belly muscles, the latissimus dorsi and deep pectoral, which are located only in the 6th to 9th vertebrae sections, were found to have heritability estimates ranging from 0.21 to 0.29 and 0.23 to 0.35, respectively. Strong heritability estimates were observed in the 7th to 13th sections of cutaneous trunci muscle ranging from 0.42 to 0.66. Genetic correlations of latissimus dorsi m. with belly length were positive (0.50), while cutaneous trunci m. with belly weight also revealed a positive relationship that ranged from 0.35 to 0.47. The estimated genetic parameters indicate that belly weight can be improved by genetic selection. Differences in the levels of heritability occurred among various parameters of Yorkshire pork belly, which should be considered when performing selection to improve pork belly quality. Moreover, these results can provide valuable information that can be used as the basis for further investigations to improve pork belly.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.11
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• pp.1657-1663
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• 2019

Objective: A genome-based best linear unbiased prediction (GBLUP) method was applied to evaluate accuracies of genomic estimated breeding value (GEBV) of carcass and reproductive traits in Berkshire, Duroc and Yorkshire populations in Korean swine breeding farms. Methods: The data comprised a total of 1,870, 696, and 1,723 genotyped pigs belonging to Berkshire, Duroc and Yorkshire breeds, respectively. Reference populations for carcass traits consisted of 888 Berkshire, 466 Duroc, and 1,208 Yorkshire pigs, and those for reproductive traits comprised 210, 154, and 890 dams for the respective breeds. The carcass traits analyzed were backfat thickness (BFT) and carcass weight (CWT), and the reproductive traits were total number born (TNB) and number born alive (NBA). For each trait, GEBV accuracies were evaluated with a GEBV BLUP model and realized GEBVs. Results: The accuracies under the GBLUP model for BFT and CWT ranged from 0.33-0.72 and 0.33-0.63, respectively. For NBA and TNB, the model accuracies ranged 0.32 to 0.54 and 0.39 to 0.56, respectively. The realized accuracy estimates for BFT and CWT ranged 0.30 to 0.46 and 0.09 to 0.27, respectively, and 0.50 to 0.70 and 0.70 to 0.87 for NBA and TNB, respectively. For the carcass traits, the GEBV accuracies under the GBLUP model were higher than the realized GEBV accuracies across the breed populations, while for reproductive traits the realized accuracies were higher than the model based GEBV accuracies. Conclusion: The genomic prediction accuracy increased with reference population size and heritability of the trait. The GEBV accuracies were also influenced by GEBV estimation method, such that careful selection of animals based on the estimated GEBVs is needed. GEBV accuracy will increase with a larger sized reference population, which would be more beneficial for traits with low heritability such as reproductive traits.

• Animal Bioscience
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• v.34 no.12
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• pp.1903-1911
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• 2021

Objective: The objective of this study was to estimate the genetic parameters and various litter trait trends of Danish pigs in South Vietnam, including the number born alive (NBA), number weaned (NW), and litter weight at the 21st day (LW21). Methods: Records of 936 Yorkshire sows with 3361 litters and 973 Landrace sows with 3161 litters were used to estimate the variance components, genetic parameters, and trends of NBA, NW, and LW21. The restricted maximum likelihood method was applied using VCE6 software to obtain the variance components and genetic parameters. Thereafter, the best linear unbiased prediction procedure with an animal model was applied using PEST software to estimate the breeding values of the studied traits. Results: The heritability estimates were low, ranging from 0.12 to 0.21 for NBA, 0.03 to 0.04 for NW, and from 0.11 to 0.13 for LW21. The genetic correlation between the NBA and NW was relatively strong in both breeds, at 0.77 and 0.60 for Yorkshire and Landrace, respectively. Similarly, the genetic correlation between the NW and LW21 was considerably stronger in Landrace pigs (0.71) than in Yorkshire pigs (0.48). The estimates of annual genetic progress were 0.0431, 0.0233, and 0.0461 for NBA, NW, and LW21 in Landrace pigs and 0434, 0.0202, and 0.0667 for NBA, NW, and LW21 in Yorkshire pigs, respectively. Conclusion: The positive genetic trends estimated for the additive genetic values of the selected traits indicated that the current breeding system has achieved favorable results.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.91.1-91.1
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• 2008