• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1675-1683
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• 2005

In the process of crossbreeding, the linkage disequilibria between the quantitative trait loci (QTL) and their linked markers were reduced gradually with increasing generations. To study the potential of QTL mapping using the crossbred population, we presented a mixed effect model that treated the mean allelic value of the different founder populations as the fixed effect and the allelic deviation from the population mean as random effect. It was assumed that there were fifty QTLs having effect on the trait variation, the population mean and variance were divided to each QTL in founder generation in our model. Only the additive effect was considered in this model for simulation. Six schemes (S1-S6) of crossbreeding were studied. The selection index was used to evaluate the synthetic breeding value of two traits of the individual in the scheme of S2, S4 and S6, and the individuals with high selection index were chosen as the parents of the next generation. Random selection was used in the scheme of S1, S3 and S5. In this study, we premised a QTL explained 40% of the genetic variance was located in a region of 20 cM by the linkage analysis previously. The log likelihood ratio (log LR) was calculated to determine the presence of a QTL at the particular chromosomal position in each of the generations from the fourth to twentieth. The profiles of log LR and the number of the highest log LR located in the region of 5, 10 and 20 cM were compared between different generations and schemes. The profiles and the correct number reduced gradually with the generations increasing in the schemes of S2, S4 and S6, but both of them increased in the schemes of S1, S3 and S5. From the results, we concluded that the crossbreeding population undergoing random selection was suitable for improving the resolution of QTL mapping. Even experiencing index selection, there was still enough variation existing within the crossbred population before the fourteenth generation that could be used to refine the location of QTL in the chromosome region.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.993-999
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• 2010

Serum lysozyme gene is one of the important genes influencing the immune system as its product can cause lysis of bacterial cell wall by cleaving the peptidoglycan layer. The present investigation on the serum lysozyme gene of Indian riverine buffalo was undertaken with the objectives to identify and characterize single nucleotide polymorphic patterns by PCR-SSCP method as well as to study the effect of different genotypes on serum lysozyme activity and somatic cell count. A total of 280 animals comprising four different famous bubaline breeds (Murrah, Mehsana, Surti and Bhadawari), spread over six different farms across the country were used for this study. A 276 bp (partial intron 2, complete exon 3 and partial intron 3) fragment of lysozyme gene was screened for polymorphism using the SSCP technique. Four genotypes namely AA, AB, BC and AC were observed, out of which BC genotype was found to be the most frequent. Among these three alleles, C allele (0.38) was most prevalent in these populations. Various SSCP allelic variants were cloned for sequencing and sequences were submitted to NCBI Genbank. From the alignment of the nucleotide sequences of various allelic variants, it was found that there were differences in 12 positions among the alleles, out of which maximum variation (at 8 places) was found in the intronic region. The allele A was closer to allele-C than allele-B. Allele B was phylogenetically equidistant from both of the other alleles. Mean lysozyme activity determined in serum samples of different animals of Murrah buffalo was $27.35{\pm}2.42\;{\mu}g$ per ml of serum, whereas the mean somatic cell count was $1.25{\pm}0.13{\times}10^5$ cells per ml of milk. The SSCP pattern-wise effects of various genotypes on lysozyme activity and SCC were analyzed. Although the mean values were apparently different in various genotypes, these differences were statistically non-significant. It can be concluded that the riverine buffaloes are sufficiently polymorphic with respect to serum lysozyme gene. The absence of AA genotype in Bhadawari breed of buffalo can be considered as a marker for breed characterization. The difference of four nucleotides in exon-3 indicates high selection pressure on the gene.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.147-150
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• 2007

Most expressed HLA (human leukocyte antigen) loci exhibit a remarkable degree of allelic polymorphism, which derives from sequence differences predominantly localized to discrete hypervariable regions of the amino terminal domain of the molecule. In this study, the HLA-B genotypes were determined in twenty students unrelated koreans using the PCR-SSP (polymerase chain reaction-sequence specific primer) technique. Several specific primer pairs in assigning the HLA-B gene were used ($B^{\ast}4001/4007$, $B^{\ast}4901/5001/4501$, $B^{\ast}3701$, $B^{\ast}5801$). The results of PCR-SSP, the HLA-B3701 primer was detected one (5%), the $HLA-B^{\ast}5801$ were detected four (20%), the $HLA-B^{\ast}4001/4007$ were detected nineteen (95%) and the $HLA-B^{\ast}4901/5001/4501$ were detected twenty. This study shows that the PCR-SSP technique is relatively simple, fast and a practical tool for the determination of the HLA-B genotypes. Moreover, these results genotype frequency of the HLA-B gene could be useful for database study before being applied to individual identification and transplantation immunity.

• BMB Reports
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• v.29 no.1
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• pp.45-51
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• 1996

Most expressed HLA loci exhibit a remarkable degree of allelic polymorphism, which derives from sequence differences predominantly localized to discrete hypervariable regions of the amino-terminal domain of the molecule. In this study, the HLA-DRB1 genotypes were determined in eighteen control cell lines and 112 unrelated Koreans using the PCR-SSP (Polymerase Chain Reaction-Sequence Specific Primer) technique. 29 specific primer pairs in assigning the DRB1 gene were used. The results of control cells correlated well with the data which was previously reported. The heterozygosity and homozygosity of the DRB1 gene were 0.786 and 0.214, respectively. In a total of 41 different DRB1 alleles and 83 genotypes, the most frequent allele and genotype were DRB1*04 and DRB1*0901/1501, respectively. This study shows that the PCR-SSP technique is relatively simple, fast and a practical tool for the determination of the HLA-DRBI genotypes. Moreover, these results-allele and genotype frequency and heterozygosity of the HLA DRB1 gene-could be useful for database study before being applied to individual identification and transplantation immunity.

• Genomics & Informatics
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• v.11 no.2
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• pp.93-96
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• 2013

The prediction of externally visible characteristics from DNA has been studied for forensic genetics over the last few years. Externally visible characteristics include hair, skin, and eye color, height, and facial morphology, which have high heritability. Recent studies using genome-wide association analysis have identified genes and variations that correlate with human visible phenotypes and developed phenotype prediction programs. However, most prediction models were constructed and validated based on genotype and phenotype information on Europeans. Therefore, we need to validate prediction models in diverse ethnic populations. In this study, we selected potentially useful variations for forensic science that are associated with hair and eye color, iris pattern, and facial morphology, based on previous studies, and analyzed their frequencies in 1,920 Koreans. Among 20 single nucleotide polymorphisms (SNPs), 10 SNPs were polymorphic, 6 SNPs were very rare (minor allele frequency < 0.005), and 4 SNPs were monomorphic in the Korean population. Even though the usability of these SNPs should be verified by an association study in Koreans, this study provides 10 potential SNP markers for forensic science for externally visible characteristics in the Korean population.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.752-756
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• 2011

Polymorphism of the second exon of the caprine leukocyte antigen-DRB3 gene (CLA-$DRB3^*02$) was investigated in this study. The 285 bp PCR product of 258 individuals from 10 domestic goat breeds in Southwest China was digested with restriction endonucleases PstI and HaeIII and then genotyped. Three alleles and 4 restriction digestion profiles were distinguished by digestion of the PCR fragment by PstI, and 8 alleles and 13 genotypes by HaeIII. For HaeIII restriction enzyme sites, the Chi-square ($X^2$) test showed that all goat breeds in this study did not fit with the Hardy-Weinberg equilibrium (p<0.01 or p<0.05). The highly polymorphic nature of CLA-$DRB3^*02$ was demonstrated and the ranges of gene heterozygosity (He) and polymorphism information content (PIC) were 0.36-0.63 and 0.32-0.55, respectively. Clustering analysis showed that the 10 goat breeds clustered into two groups and Dazu Black goat had a close genetic relationship with Chengdu Grey, Jintang Black and Nanjiang Yellow goats.

• BMB Reports
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• v.40 no.2
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• pp.172-179
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• 2007

PCR-mediated recombination describes the process of in vitro chimera formation from related template sequences present in a single PCR amplification. The high levels of genetic redundancy in eukaryotic genomes should make recombination artifacts occur readily. However, few evolutionary biologists adequately consider this phenomenon when studying gene lineages. The cytosolic glyceraldehyde-3-phosphate dehydrogenase gene (GapC), which encodes a NADP-dependent nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase in the cytosol, is a classical lowcopy nuclear gene marker and is commonly used in molecular evolutionary studies. Here, we report on the occurrence of PCR-mediated recombination in the GapC gene family of Hibiscus tiliaceus. The study suggests that recombinant areas appear to be correlated with DNA template secondary structures. Our observations highlight that recombination artifacts should be considered when studying specific and allelic phylogenies. The authors suggest that nested PCR be used to suppress PCRmediated recombination.

• Parasites, Hosts and Diseases
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• v.56 no.2
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• pp.175-181
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• 2018

The giant roundworm Ascaris infects pigs and people worldwide and causes serious diseases. The taxonomic relationship between Ascaris suum and Ascaris lumbricoides is still unclear. The purpose of the present study was to investigate the genetic diversity and population genetic structure of 258 Ascaris specimens from humans and pigs from 6 sympatric regions in Ascaris-endemic regions of China using existing simple sequence repeat data. The microsatellite markers showed a high level of allelic richness and genetic diversity in the samples. Each of the populations demonstrated excess homozygosity (Ho0). According to a genetic differentiation index (Fst=0.0593), there was a high-level of gene flow in the Ascaris populations. A hierarchical analysis on molecular variance revealed remarkably high levels of variation within the populations. Moreover, a population structure analysis indicated that Ascaris populations fell into 3 main genetic clusters, interpreted as A. suum, A. lumbricoides, and a hybrid of the species. We speculated that humans can be infected with A. lumbricoides, A. suum, and the hybrid, but pigs were mainly infected with A. suum. This study provided new information on the genetic diversity and population structure of Ascaris from human and pigs in China, which can be used for designing Ascaris control strategies. It can also be beneficial to understand the introgression of host affiliation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7091-7094
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• 2013

DNA repair capacity is crucial in maintaining cellular functions and homeostasis. However, it can be altered based on DNA sequence variations in DNA repair genes and this may lead to the development of many diseases including malignancies. Identification of genetic polymorphisms responsible for reduced DNA repair capacity is necessary for better prevention. Homologous recombination (HR), a major double strand break repair pathway, plays a critical role in maintaining the genome stability. The present study was performed to determine the frequency of the HR gene XRCC3 Exon 7 (C18067T, rs861539) polymorphisms in Saudi Arabian population in comparison with epidemiological studies by "MEDLINE" search to equate with global populations. The variant allelic (T) frequency of XRCC3 (C>T) was found to be 39%. Our results suggest that frequency of XRCC3 (C>T) DNA repair gene exhibits distinctive patterns compared with the Saudi Arabian population and this might be attributed to ethnic variation. The present findings may help in high-risk screening of humans exposed to environmental carcinogens and cancer predisposition in different ethnic groups.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.927-930
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• 2006

This study was conducted to investigate potential effects of previously identified QTL regions on carcass traits in Hanwoo. The data analyzed in this study was collected from 326 steers of 67 proven sire. Thirteen micorsatellite markers spanning QTL regions on bovine chromosomes 1 and 14 were genotyped in 326 steers. The following breeding values were analyzed for QTL effects. Cold carcass weight breeding value (CCWBV), longissimus muscle area breeding value (LMABV), marbling score breeding value (MSBV) and backfat thickness breeding value (BFTBV). Chi-square tests were performed to compare frequencies of individual allele between high and low breeding value groups. Significant differences of allele frequencies in BMS711, MCM130, BMS4049, and BMS2263 were found. And also, in RM180, BL1029, BM4305, and BMS2055 there were significant differencies of allele frequencies. These results showed a potential application for investigation of putative QTL locations.