Zipf's law in importance of genes for cancer classification using microarray data
Zipf's law in importance of genes for cancer classification using microarray data
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DOI:
10.1006/jtbi.2002.3145
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发表时间:
2002-12-21
影响因子:
2
通讯作者:
Yang, YN
中科院分区:
文献类型:
--
作者:
Li, WT;Yang, YN
Using a measure of how differentially expressed a gene is in two biochemically/phenotypically different conditions, we can rank all genes in a microarray dataset. We have shown that the falling-off of this measure (normalized maximum likelihood in a classification model such as logistic regression) as a function of the rank is typically a power-law function. This power-law function in other similar ranked plots are known as the Zipf's law, observed in many natural and social phenomena. The presence of this power-law function prevents an intrinsic cutoff point between the "important" genes and "irrelevant" genes. We have shown that similar power-law functions are also present in permuted dataset, and provide an explanation from the well-known chi(2) distribution of likelihood ratios. We discuss the implication of this Zipf's law on gene selection in a microarray data analysis, as well as other characterizations of the ranked likelihood plots such as the rate of fall-off of the likelihood. (C) 2002 Elsevier Science Ltd. All rights reserved.