• 응용통계연구
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• 제23권4호
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• pp.705-713
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• 2010

마이크로어레이 실험 결과로부터 생존예측지표를 개발하는 일은 관찰 유전자수가 환자의 수보다 훨씬 많고 또 반응변수가 중도절단이 포함된 생존시간이기 때문에 어려운 작업이다. 또한 개별유전자 분석의 문제점이 대두되면서 동일한 대사기능을 수행하는 유전자들의 집합을 대상으로 분석하는 방법이 대두되고 있다. DLBCL 환자들의 마이크로어레이 유전자 발현 자료와 생존시간, 유전자들의 대사경로 정보를 바탕으로 생물학적 해석이 쉬운 생존예측지표를 찾고 그 정확성을 검정하는 pilot study를 실시하였다. 또한 유전자 걸러내기가 지표의 효율성에 미치는 영향력도 비교하여 보았다.

• 한국수정란이식학회지
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• 제30권2호
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• pp.99-107
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• 2015

The aim of the present study was to identify coat color associated genes that are differentially expressed in mature Korean brindle cattle (KBC) with different coat colors and in Hanwoo cows. KBC calves, before and after coat color appearance, were included. Total cellular RNA was isolated from the tail hair cells and used for microarray. The number of expressed coat color associated genes/probes was 5813 in mature KBC and Hanwoo cows. Among the expressed coat color associated genes/probes, 167 genes were the coat color associated genes listed in the Gene card database and 125 genes were the pigment and melanocyte genes listed in the Gene ontology_bovine database. There were 23 genes/probes commonly listed in both databases and their expressions were further studied. Out of the 23 genes/probes, MLPH, PMEL, TYR and TYRP1 genes were expressed at least two fold higher (p<0.01) levels in KBC with brindle color than either Hanwoo or KBC with brown color. TYRP1 expression was 22.96 or 19.89 fold higher (p<0.01) in KBC with brindle color than either Hanwoo or KBC with brown color, respectively, which was the biggest fold difference. The hierarchical clustering analysis indicated that MLPH, PMEL, TYR and TYRP1 were the highly expressed genes in mature cattle. There were only a few genes differentially expressed after coat color appearance in KBC calves. Studies on the regulation and mechanism of gene expression of highly expressed genes would be next steps to better understand coat color determination and to improve brindle coat color appearance in KBC.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1924-1929
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• 2007

오늘날 인간 프로젝트와 같은 종합적 인 연구의 궁극적 목적을 달성하기 위해서는 이 들 연구로부터 획득한 대량의 관련 데이터에 대해 새로운 현실적 의미를 부여할 수 있어야 한다. 마이크로어레이를 기반으로 하는 종양 분류 방법은 종양 종류에 따라 다르게 발현되는 유전자 양상을 통계적으로 발견함으로써 정확한 종양 분류에 기여 할 수 있다. 따라서 현재의 마이크로어레이 기술을 이용해서 효과적으로 종양을 분류하기 위해서는 특정 종양 분류와 밀접하게 관련이 있는 정보력 있는 유전자를 선택하는 과정이 필수적이다. 본 논문에서는 암에 걸린 흰쥐 외피 기간 세포 분화 실험에서 얻어진 3840 유전자의 마이크로어레이 cDNA를 이용해 데이터의 정규화를 거쳐 정보력 있는 유전자 목록을 별도로 추출하여 보다 정확한 종양 분류 모델을 구축하고 각각의 실험 결과들을 비교 분석함으로써 성능평가를 하였다. 피어슨 적률 상관 계수를 이용하여 선택된 유전자들을 멀티퍼셉트론 분류기로 분류한 결과 98.6%의 정확도를 보였다.

• 대한한방내과학회지
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• 제30권3호
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• pp.594-603
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• 2009

Objectives : ICH breaks down blood vessels within the brain parenchyma, which finally leads to neuronal loss, drugs to treat ICH have not yet been established. In this experiment, we measured the effect of Woowhangchongshim-won (WWCSW) on intracerebral hemorrhage (ICH) in rat using microarray technology. Methods : We measured the effect of WWCSW on ICH in rat using microarray technology. ICH was induced by injection of collagenase type IV, and total RNA was isolated. Image files of microarray were measured using a ScanArray scanner, and the criteria of the threshold for up- and down-regulation was 2 fold. Hierarchical clustering was implemented using CLUSTER and TREEVIEW program, and for Ontology analysis. GOSTAT program was applied in which p-value was calculated by Chi square or Fisher's exact test based on the total array element. Results : WWCSW-treatment restored the gene expression altered by ICH-induction in brain to the levels of 76.0% and 70.1% for up- and down-regulated genes, respectively. Conclusion : Co-regulated genes by ICH model of rat could be used as molecular targets for therapeutic effects of drug including WWCSW. That is, the presence of co-regulated genes may represent the importance of these genes in ICH in the brain and the change of expression level of these co-regulated genes would also indicate the functional change of brain tissue.

• 한국정보통신학회논문지
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• 제10권12호
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• pp.2283-2288
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• 2006

최근 생명 정보학 기술의 발달로 마이크로 단위의 실험조작이 가능해짐에 따라 하나의 chip상에서 전체 genome의 expression pattern을 관찰할 수 있게 되었고, 동시에 수 만개의 유전자들 간의 상호작용도 연구 가능하게 되었다. 이처럼 DNA 마이크로어레이 기술은 복잡한 생물체를 이해하는 새로운 방향을 제시해주게 되었다. 따라서 이러한 기술을 통해 얻어진 대량의 유전자 정보들을 효과적으로 분석하는 방법이 시급하다. 본 논문에서는 실험용 데이터로 하버드대학교의 바이오인포메틱스 코어 그룹의 샘플데이터 이용하여 마이크로어레이 실험에서 다양한 원인에 의해 발생하는 잡음(noise)을 줄이거나 제거하는 과정인 표준화 과정을 거쳐 특징 추출방법인 베이지안 알고리즘 ASA(Adaptive Simulated Annealing) 방법을 이용하여 데이터를 2개의 클래스로 나누고, 정확도를 평가하는 시스템을 설계하고 구현하였다. Lowess 표준화 후 98.23%의 정확도를 보였다.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2000년도 제28회 학술심포지엄
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• pp.3-8
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• 2000

The complete genome sequence of a Gram-positive bacterium .Bacillus subtilis has recently been reported and it is now clear that more than 50% of its ORFs have no known function (1). To study the global gene expression in B. subtilis at single gene resolution, we have tested the glass DNA microarrays in a step-wise fashion. As a preliminary experiment, we have created arrays of PCR products for 14 ORF whose transcription patterns have been well established through transcriptional mapping analysis. We measured changes in mRNA transcript levels between early exponential and stationary phase by hybridizing fluorescently labeled cDNA (with Cy3-UTP and Cy5-UTP) onto the array. We then compared the microarray data to confirm that the transcription patterns of these genes are well consistent with the known Northern analysis data. Since the preliminary test has been successful, we scaled up the experiments to ${\sim}$94% of the 4,100 annotated ORFs for the complete genome sequence of B. subtilis. Using this whole genomic microarray, we searched genes that are catabolite-repressive and those that are under the control of ${\sigma}^{Y}$, one of the functionally unknown ECF sigma factors. From these results, we here report that we have established DNA microarray techniques that are applicable for the whole genome of B. subtilis.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2002년도 춘계 학술발표회 논문집
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• pp.85-90
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• 2002

Microarray technology allows the monitoring of expression levels for thousands of genes simultaneously. In time-course experiments in which gene expression is monitored over time we are interested in testing gene expression profiles for different experimental groups. We propose a statistical test based on the ANOVA model to identify genes that have different gene expression profiles among experimental groups in time-course experiments. Using this test, we can detect genes that have different gene expression profiles among experimental groups. The proposed model is illustrated using cDNA microarrays of 3,840 genes obtained in an experiment to search for changes in gene expression profiles during neuronal differentiation of cortical stem cells.

• 응용통계연구
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• 제24권6호
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• pp.1103-1113
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• 2011

Gene expression data is obtained through many stages of an experiment and errors produced during the process may cause missing values. Due to the distinctness of the data so called 'small n large p', genes have to be selected for statistical analysis, like classification analysis. For this reason, imputation and gene selection are important in a microarray data analysis. In the literature, imputation, gene selection and classification analysis have been studied respectively. However, imputation, gene selection and classification analysis are sequential processing. For this aspect, we compare the performance of classification methods after imputation and gene selection methods are applied to microarray data. Numerical simulations are carried out to evaluate the classification methods that use various combinations of the imputation and gene selection methods.

• 응용통계연구
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• 제21권3호
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• pp.523-535
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• 2008

본 연구의 목적은 마이크로어레이 자료로부터 암 또는 질병에 유의한 유전자집단을 찾아내는 보다 효과적인 방법을 제안하고자 하는 것이다. 유전자 집단 분석의 대표적 방법인 PAGE와 GSEA의 한계점을 살펴보고, 그것을 보완하기 위한 GSA-AT라는 방법을 제안하였다. 모의실험과 실제자료실험을 통해 분석해 본 결과 본 연구에서 제안한 GSA-AT 방법에서 더 의미 있는 결과를 도출하였다.

• Genomics & Informatics
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• 제4권3호
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• pp.129-132
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• 2006

Toxicogenomics has recently emerged in the field of toxicology and the DNA microarray technique has become common strategy for predictive toxicology which studies molecular mechanism caused by exposure of chemical or environmental stress. Although microarray experiment offers extensive genomic information to the researchers, yet high dimensional characteristic of the data often makes it hard to extract meaningful result. Therefore we developed toxicant enrichment analysis similar to the common enrichment approach. We also developed web-based system graPT to enable considerable prediction of toxic endpoints of experimental chemical.