• Genomics & Informatics
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• v.17 no.1
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• pp.9.1-9.5
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• 2019

In previous studies, we demonstrated that some sites in the first intron likely regulate gene expression. In the present work, we sought to further confirm the functional relevance of first intron sites by estimating the quantity of rare alleles in the first intron. A basic hypothesis posited herein is that genomic regions carrying more functionally important sites will have a higher proportion of rare alleles. We estimated the proportions of rare single nucleotide polymorphisms with a minor allele frequency < 0.01 located in several histone marks in the first introns of various genes, and compared them with those in other introns and those in 2-kb upstream regions. As expected, rare alleles were found to be significantly enriched in most of the regulatory sites located in the first introns. Meanwhile, transcription factor binding sites were significantly more enriched in the 2-kb upstream regions (i.e., the regions of putative promoters of genes) than in the first introns. These results strongly support our proposal that the first intron sites of genes may have important regulatory functions in gene expression independent of promoters.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.3
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• pp.107-111
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• 2019

Objective: Spermatogenesis is a complex process that is regulated by a number of genes, some of which are involved in folate-dependent 1-carbon metabolism. Methionine synthase (encoded by MTR) is a key enzyme participating in this pathway. This study aimed to investigate the relationship of the MTR 2756A > G polymorphism with idiopathic male fertility in the Iranian population. Methods: The participants of this study included 100 men with idiopathic infertility and 100 healthy men as the control group. Genotyping of MTR 2756A > G was performed using the polymerase chain reaction and restriction fragment length polymorphism technique. The obtained data were analyzed using SPSS ver. 20.0 with a level of confidence of p< 0.05. Results: The frequencies of the A and G alleles at this locus were 77% and 23% in infertile patients and 84% and 16% in the control group, respectively. The frequencies of the GG, GA, and AA genotypes were 5%, 36%, and 59% in the infertile patients versus 3%, 27%, and 70% in the control group, respectively. No significant difference was observed in any genetic models. Conclusion: In general, the findings of this study suggest that the MTR 2756A > G single-nucleotide polymorphism is not a predisposing factor for idiopathic infertility in men.

• Fisheries and Aquatic Sciences
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• v.22 no.8
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• pp.18.1-18.5
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• 2019

The development of sex-specific genetic assays in a species provides both a method for identifying the system of sex determination and a valuable tool to address questions of conservation and management importance. In this study, we focused on the identification of single nucleotide polymorphisms (SNPs) that differentiate genetic sex in burbot Lota lota. Burbot are the only true freshwater representative of the cod family and a species of conservation and management importance throughout Eurasia and North America. To identify sex-specific SNPs, we utilized restriction site-associated DNA sequencing (RADseq) to interrogate thousands of SNPs in burbot samples of known phenotypic sex. We discovered 170,569 biallelic SNPs, none of which fit the pattern expected under female heterogamety. However, we identified 22 SNPs that fit the pattern expected under male heterogamety (males heterozygous XY, females fixed XX) and, from these, developed two genetic assays that robustly (~ 97% genotyping success) and accurately (> 99% correct) sexed burbot samples. These sex-specific genetic assays will benefit growing conservation aquaculture programs for this species and allow future assessments of sex-specific migration, growth, and mortality.

• Biomedical Science Letters
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• v.27 no.3
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• pp.187-194
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• 2021

Platelets are derived from fragments formed in the cytoplasm of bone marrow megakaryocytes. Platelet count (PLT) can be altered by factors such as platelet production, destruction, and inflammation. In a previous study, the significant single nucleotide polymorphisms (SNP) were reported by the genome-wide association study (GWAS) for PLT in Koreans. In this study, it was confirmed whether significant SNPs were replicated in the HEXA (The Health Examinees) cohort. As a result, the SNPs of the THPO (rs6141), BAK1 (rs210314, rs9296095), GGNBP1 (rs75080135), ACAD10 (rs6490294), and ABCC4 (rs4148441) were significantly correlated with PLT (P < 10^-8). At the same time, it was confirmed that the direction of influence was the same according to the genotype. In conclusion, it can be seen that common SNPs are associated with the platelet count regardless of the cohort for Koreans.

• Genomics & Informatics
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• v.20 no.2
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• pp.17.1-17.11
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• 2022

Genetic associations have been quantified using a number of statistical measures. Entropy-based mutual information may be one of the more direct ways of estimating the association, in the sense that it does not depend on the parametrization. For this purpose, both the entropy and conditional entropy of the phenotype distribution should be obtained. Quantitative traits, however, do not usually allow an exact evaluation of entropy. The estimation of entropy needs a probability density function, which can be approximated by kernel density estimation. We have investigated the proper sequence of procedures for combining the kernel density estimation and entropy estimation with a probability density function in order to calculate mutual information. Genotypes and their interactions were constructed to set the conditions for conditional entropy. Extensive simulation data created using three types of generating functions were analyzed using two different kernels as well as two types of multifactor dimensionality reduction and another probability density approximation method called m-spacing. The statistical power in terms of correct detection rates was compared. Using kernels was found to be most useful when the trait distributions were more complex than simple normal or gamma distributions. A full-scale genomic dataset was explored to identify associations using the 2-h oral glucose tolerance test results and γ-glutamyl transpeptidase levels as phenotypes. Clearly distinguishable single-nucleotide polymorphisms (SNPs) and interacting SNP pairs associated with these phenotypes were found and listed with empirical p-values.

• Genomics & Informatics
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• v.20 no.2
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• pp.16.1-16.12
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• 2022

Various methodologies for the genetic analysis of longitudinal data have been proposed and applied to data from large-scale genome-wide association studies (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with traits of interest and to detect SNP-time interactions. We recently proposed a grid-based Bayesian mixed model for longitudinal genetic data and showed that our Bayesian method increased the statistical power compared to the corresponding univariate method and well detected SNP-time interactions. In this paper, we further analyze longitudinal obesity-related traits such as body mass index, hip circumference, waist circumference, and waist-hip ratio from Korea Association Resource data to evaluate the proposed Bayesian method. We first conducted GWAS analyses of cross-sectional traits and combined the results of GWAS analyses through a meta-analysis based on a trajectory model and a random-effects model. We then applied our Bayesian method to a subset of SNPs selected by meta-analysis to further discover SNPs associated with traits of interest and SNP-time interactions. The proposed Bayesian method identified several novel SNPs associated with longitudinal obesity-related traits, and almost 25% of the identified SNPs had significant p-values for SNP-time interactions.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.595-606
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• 2022

Industrial pig breeding has used the Duroc breed and terminal sires in a three-way crossbred system in Korea. This study identified the gene variation patterns related to carcass quality in crossbred pigs ([Landrace × Yorkshire] × Duroc) using whole-exome sequencing (WES). This study used crossbred pigs and divided them into two groups (first plus grade, n = 5; second grade, n = 5). Genomic DNA samples extracted from the loin muscles of both groups were submitted for WES. A set of validated single-nucleotide polymorphisms (SNPs: n = 102) were also subjected to the Kompetitive allele-specific polymerase chain reaction (KASP) to confirm the WES results in the loin muscles. Based on the WES, SNPs associated with meat quality were found on chromosomes 5, 10, and 15. We identified variations in three of the candidate genes, including kinesin family member 5B (KIF5B), GLI family zinc finger 2 (GLI2), and KIF26B, that were associated with meat color, marbling score, and backfat thickness. These genes were associated with meat quality and the mitogen-activated protein kinase (MAPK) and Hedgehog (Hh) signaling pathways in the crossbred pigs. These results may help clarify the mechanisms underlying high-quality meat in pigs.

• Journal of Mushroom
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• v.19 no.4
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• pp.336-340
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• 2021

The cleaved amplified polymorphic sequence (CAPS) marker uses a restriction enzyme recognition site resulting from single nucleotide polymorphisms and insertions and deletions on the DNA sequence. This technique does not require expensive equipment, the process is simple, and clear results can be obtained reliably. In this study, Agaricus bisporus cultivars SaeA, SaeDo, SaeHan, SaeYeon, SaeJeong, Dodam, Seolgang, Dahyang, Hogam, and Hadam developed in Korea were discriminated using four CAPS markers. Our results indicated that it is possible to distinguish the ten cultivars and determine the genetic diversity among them.

• Genomics & Informatics
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• v.21 no.2
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• pp.26.1-26.9
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• 2023

Stevens-Johnson syndrome (SJS) produces a severe hypersensitivity reaction caused by Herpes simplex virus or mycoplasma infection, vaccination, systemic disease, or other agents. Several studies have investigated the genetic susceptibility involved in SJS. To provide further genetic insights into the pathogenesis of SJS, this study prioritized high-impact, SJS-associated pathogenic variants through integrating bioinformatic and population genetic data. First, we identified SJS-associated single nucleotide polymorphisms from the genome-wide association studies catalog, followed by genome annotation with HaploReg and variant validation with Ensembl. Subsequently, expression quantitative trait locus (eQTL) from GTEx identified human genetic variants with differential gene expression across human tissues. Our results indicate that two variants, namely rs2074494 and rs5010528, which are encoded by the HLA-C (human leukocyte antigen C) gene, were found to be differentially expressed in skin. The allele frequencies for rs2074494 and rs5010528 also appear to significantly differ across continents. We highlight the utility of these population-specific HLA-C genetic variants for genetic association studies, and aid in early prognosis and disease treatment of SJS.

• Genomics & Informatics
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• v.21 no.3
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• pp.28.1-28.13
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• 2023

Mild cognitive impairment (MCI) is a clinical syndrome characterized by the onset and evolution of cognitive impairments, often considered a transitional stage to Alzheimer's disease (AD). The genetic traits of MCI patients who experience a rapid progression to AD can enhance early diagnosis capabilities and facilitate drug discovery for AD. While a genome-wide association study (GWAS) is a standard tool for identifying single nucleotide polymorphisms (SNPs) related to a disease, it fails to detect SNPs with small effect sizes due to stringent control for multiple testing. Additionally, the method does not consider the group structures of SNPs, such as genes or linkage disequilibrium blocks, which can provide valuable insights into the genetic architecture. To address the limitations, we propose a Bayesian bi-level variable selection method that detects SNPs associated with time of conversion from MCI to AD. Our approach integrates group inclusion indicators into an accelerated failure time model to identify important SNP groups. Additionally, we employ data augmentation techniques to impute censored time values using a predictive posterior. We adapt Dirichlet-Laplace shrinkage priors to incorporate the group structure for SNP-level variable selection. In the simulation study, our method outperformed other competing methods regarding variable selection. The analysis of Alzheimer's Disease Neuroimaging Initiative (ADNI) data revealed several genes directly or indirectly related to AD, whereas a classical GWAS did not identify any significant SNPs.