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Activity Number:
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275
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Type:
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Contributed
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Date/Time:
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Tuesday, August 4, 2009 : 8:30 AM to 10:20 AM
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Sponsor:
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Section on Nonparametric Statistics
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| Abstract - #304821 |
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Title:
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How to Dig for DEGs
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Author(s):
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Lena Granovsky*+ and Paul D. Feigin
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Companies:
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Technion and Technion--Israel Institute of Technology
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Address:
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Technion city, Faculty of industrial Engineering , Haifa, International, 32000, Israel
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Keywords:
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Permutation methods ; empirical Bayes ; microarray experiments ; null distribution ; differentially expressed genes
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Abstract:
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Permutation methods are commonly used to estimate a null distribution of non-differentially expressed genes (DEGs) in microarray experiments. We extend the empirical Bayes approach proposed by Efron by suggesting a number of permutation procedures, used for an empirical test of the appropriate null hypothesis. We examine the difference between applying these methods and a theoretical null distribution. The permutation procedures proposed in this study are applied to the data from two experiments. We show that the choice of the permutation method should depend on the experimental design. Various choices of such methods lead to different estimates of the null distribution and consequently to different lists of genes identified as significant. We also indicate that in many applications the usual assumption of the null distribution is incorrect and might produce an incorrect list of DEGs.
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