• Title/Summary/Keyword: Differential expression analysis

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Identifying statistically significant gene sets based on differential expression and differential coexpression (특이발현과 특이공발현을 고려한 유의한 유전자 집단 탐색)

  • Lee, Sunho
    • The Korean Journal of Applied Statistics
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    • v.29 no.3
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    • pp.437-448
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    • 2016
  • Gene set analysis utilizing biologic information is expected to produce more interpretable results because the occurrence of tumors (or diseases) is believed to be associated with the regulation of related genes. Many methods have been developed to identify statistically significant gene sets across different phenotypes; however, most focus exclusively on either the differential gene expression or the differential correlation structure in the gene set. This research provides a new method that simultaneously considers the differential expression of genes and differential coexpression with multiple genes in the gene set. Application of this NEW method is illustrated with real microarray data example, p53; subsequently, a simulation study compares its type I error rate and power with GSEA, SAMGS, GSCA and GSNCA.

Classification via principal differential analysis

  • Jang, Eunseong;Lim, Yaeji
    • Communications for Statistical Applications and Methods
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    • v.28 no.2
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    • pp.135-150
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    • 2021
  • We propose principal differential analysis based classification methods. Computations of squared multiple correlation function (RSQ) and principal differential analysis (PDA) scores are reviewed; in addition, we combine principal differential analysis results with the logistic regression for binary classification. In the numerical study, we compare the principal differential analysis based classification methods with functional principal component analysis based classification. Various scenarios are considered in a simulation study, and principal differential analysis based classification methods classify the functional data well. Gene expression data is considered for real data analysis. We observe that the PDA score based method also performs well.

Prognostic Relevance of Human Telomerase Reverse Transcriptase (hTERT) Expression in Patients with Gall Bladder Disease and Carcinoma

  • Deblakshmi, Raj Kumari;Deka, Manab;Saikia, Anjan Kumar;Sharma, Bir Kumar;Singh, Nidhi;Das, NN;Bose, Sujoy
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.7
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    • pp.2923-2928
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    • 2015
  • Background: Gallbladder carcinoma (GBC) has been stated as an Indian disease, with the highest number of cases being reported from certain districts of northeast India, which has an ethnically distinct population. Unfortunately there are no scientific reports on the underlying molecular mechanisms associated with the pathogenesis of the disease from this region. Aim: The present study evaluated the role of differential expression of human telomerase reverse transcriptase (hTERT) in the development of gall bladder anomalies. Materials and Methods: Blood and tissue samples were collected from patients undergoing routine surgical resection for clinically proven cases of gallbladder disease {cholelithiasis (CL, n=50), cholecystitis (CS, n=40) and GBC (n=30) along with adjacent histopathologically proved non-neoplastic controls (n=15)} with informed consent. Whole blood was also collected from age and sex matched healthy controls (n=25) for comparative analysis. Differential hTERT mRNA expression was evaluated by semi-quantitative rt-PCR and real-time PCR based analysis using ${\beta}$-actin as an internal control. Evaluation of differential hTERT protein expression was studied by Western blot analysis and immunoflourescence. Statistical analysis for differential expression and co-relation was performed by SPSSv13.0 software. Results: Gallbladder anomalies were mostly prevalent in females. The hTERT mRNA and protein expression increased gradiently from normal

Cloning and Characterization of Liver cDNAs That Are Differentially Expressed between Chicken Hybrids and Their Parents

  • Sun, Dong-Xiao;Wang, Dong;Yu, Ying;Zhang, Yuan
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.12
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    • pp.1684-1690
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    • 2005
  • Using mRNA differential display technique, we investigated differential gene expression in hybrids relative to their parents in a diallel cross involving four chicken breeds in order to provide an insight into the molecular basis of heterosis in chicken. The results indicated that there was extensive differential gene expression between chicken F1 hybrids and their parents which was classified into four kinds of patterns as following: (1) bands only detected in hybrid F1; (2) bands only absent in hybrid F1; (3) bands only detected in parent P1 or P2; (4) bands absent in parent P1 or P2. Forty-two differentially expressed cDNAs were cloned and sequenced, and their expression patterns were confirmed by Reverse-Northern dot blot. Sequence analysis and database searches revealed that genes showed differential expression between hybrid and parents were regulatory and functional genes involved in metabolism, mRNA splicing, transcriptional regulation, cell cycles and protein modification. These results indicated that hybridization between two parents can cause changes in expression of a variety of genes. In conclusion, that the altered pattern of gene expression in hybrids may be responsible for heterosis in chickens.

Differential Display Analysis of Gene Expression Induced under DCA Treatment in Rat Liver

  • Choi, Soon-Yong;Park, Ock-Jin
    • BMB Reports
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    • v.29 no.3
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    • pp.272-275
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    • 1996
  • The expression of genes induced by Dichloroacetate (DCA) treatment was analyzed by mRNA differential display. Purified total RNAs from rat liver treated with saline or DCA (100 mg/100 g b.w.) were reverse transcribed by using a set of oligonucleotide primers. The PCR products were resolved on a denaturing sequencing gel. PCR band representing mRNA expressed specifically in DCA-treated liver was excised and reamplified by PCR. A 120-bp c-DNA clone named IC1 was isolated and the DNA sequence of IC1 was analyzed. IC1 revealed 50% homology with 3' end of a mouse fibroblast growth factor mRNA This result indicates that DCA induces the expression of a gene which has a 50% homology with a Mouse fibroblast growth factor, and expression of this gene might be involved in non genotoxic process caused by DCA.

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How are Bayesian and Non-Parametric Methods Doing a Great Job in RNA-Seq Differential Expression Analysis? : A Review

  • Oh, Sunghee
    • Communications for Statistical Applications and Methods
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    • v.22 no.2
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    • pp.181-199
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    • 2015
  • In a short history, RNA-seq data have established a revolutionary tool to directly decode various scenarios occurring on whole genome-wide expression profiles in regards with differential expression at gene, transcript, isoform, and exon specific quantification, genetic and genomic mutations, and etc. RNA-seq technique has been rapidly replacing arrays with seq-based platform experimental settings by revealing a couple of advantages such as identification of alternative splicing and allelic specific expression. The remarkable characteristics of high-throughput large-scale expression profile in RNA-seq are lied on expression levels of read counts, structure of correlated samples and genes, larger number of genes compared to sample size, different sampling rates, inevitable systematic RNA-seq biases, and etc. In this study, we will comprehensively review how robust Bayesian and non-parametric methods have a better performance than classical statistical approaches by explicitly incorporating such intrinsic RNA-seq specific features with flexible and more appropriate assumptions and distributions in practice.

Considerations on gene chip data analysis

  • Lee, Jae-K.
    • Proceedings of the Korean Society for Bioinformatics Conference
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    • 2001.08a
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    • pp.77-102
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    • 2001
  • Different high-throughput chip technologies are available for genome-wide gene expression studies. Quality control and prescreening analysis are important for rigorous analysis on each type of gene expression data. Statistical significance evaluation of differential expression patterns is needed. Major genome institutes develop database and analysis systems for information sharing of precious expression data.

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Relationship between Differential Gene Expression in Ovary and Heterosis of Egg Number Traits in a Chicken Diallel Cross

  • Wang, Hui;Sun, Dong-Xiao;Yu, Ying;Wang, Dong;Zhang, Yuan
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.6
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    • pp.767-771
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    • 2005
  • In order to understand the molecular basis of chicken heterosis in reproduction traits, mRNA differential display (DDRT-PCR) methods were used to analyze the differential gene expression of ovary tissue between hybrids and their parental lines in a 4${\times}$4 diallel cross, involving 4 chicken breeds, which were White Plymouth Rock (E), CAU Brown (D), Silkies (C) and White Leghorn (A). Total of 331 differential displayed cDNA bands from 1,161 were displayed in the 4${\times}$4 diallel cross combinations with 30 pairs of primers, which shows the differences of gene expression between hybrids and their parental lines were very obvious in quantity and quality. Seven types of differential expression patterns were found: Co-dominance expressed pattern (T1), under-expression of parental fragments in hybrids (T2), over-expression of parental fragments in hybrids (T3), hybrid-absence expressed pattern (T4), single parentspecific expressed pattern (T5), dominant expression fragments of single parent in hybrids (T6), hybrid-specific expressed pattern (T7). Correlation analysis indicated that there were significant correlations between the pattern of T3 and the heterosis percentage of egg number of 32-week and 42-week old chickens(p<0.01), while there were negative significant correlations between the pattern of T7 and the heterosis percentage of egg number of 32-week and 42 week-old birds (p<0.01).

Anti-inflammatory effect of sulforaphane on LPS-stimulated RAW 264.7 cells and ob/ob mice

  • Ranaweera, Sachithra S.;Dissanayake, Chanuri Y.;Natraj, Premkumar;Lee, Young Jae;Han, Chang-Hoon
    • Journal of Veterinary Science
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    • v.21 no.6
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    • pp.91.1-91.15
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    • 2020
  • Background: Sulforaphane (SFN) is an isothiocyanate compound present in cruciferous vegetables. Although the anti-inflammatory effects of SFN have been reported, the precise mechanism related to the inflammatory genes is poorly understood. Objectives: This study examined the relationship between the anti-inflammatory effects of SFN and the differential gene expression pattern in SFN treated ob/ob mice. Methods: Nitric oxide (NO) level was measured using a Griess assay. The inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels were analyzed by Western blot analysis. Pro-inflammatory cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-1β, and IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). RNA sequencing analysis was performed to evaluate the differential gene expression in the liver of ob/ob mice. Results: The SFN treatment significantly attenuated the iNOS and COX-2 expression levels and inhibited NO, TNF-α, IL-1β, and IL-6 production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. RNA sequencing analysis showed that the expression levels of 28 genes related to inflammation were up-regulated (> 2-fold), and six genes were down-regulated (< 0.6-fold) in the control ob/ob mice compared to normal mice. In contrast, the gene expression levels were restored to the normal level by SFN. The protein-protein interaction (PPI) network showed that chemokine ligand (Cxcl14, Ccl1, Ccl3, Ccl4, Ccl17) and chemokine receptor (Ccr3, Cxcr1, Ccr10) were located in close proximity and formed a "functional cluster" in the middle of the network. Conclusions: The overall results suggest that SFN has a potent anti-inflammatory effect by normalizing the expression levels of the genes related to inflammation that were perturbed in ob/ob mice.

Face Image Analysis using Adaboost Learning and Non-Square Differential LBP (아다부스트 학습과 비정방형 Differential LBP를 이용한 얼굴영상 특징분석)

  • Lim, Kil-Taek;Won, Chulho
    • Journal of Korea Multimedia Society
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    • v.19 no.6
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    • pp.1014-1023
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    • 2016
  • In this study, we presented a method for non-square Differential LBP operation that can well describe the micro pattern in the horizontal and vertical component. We proposed a way to represent a LBP operation with various direction components as well as the diagonal component. In order to verify the validity of the proposed operation, Differential LBP was investigated with respect to accuracy, sensitivity, and specificity for the classification of facial expression. In accuracy comparison proposed LBP operation obtains better results than Square LBP and LBP-CS operations. Also, Proposed Differential LBP gets better results than previous two methods in the sensitivity and specificity indicators 'Neutral', 'Happiness', 'Surprise', and 'Anger' and excellence Differential LBP was confirmed.