Title
Analysis of variance components in gene expression data.
Abstract
A microarray experiment is a multi-step process, and each step is a potential source of variation. There are two major sources of variation: biological variation and technical variation. This study presents a variance-components approach to investigating animal-to-animal, between-array, within-array and day-to-day variations for two data sets. The first data set involved estimation of technical variances for pooled control and pooled treated RNA samples. The variance components included between-array, and two nested within-array variances: between-section (the upper- and lower-sections of the array are replicates) and within-section (two adjacent spots of the same gene are printed within each section). The second experiment was conducted on four different weeks. Each week there were reference and test samples with a dye-flip replicate in two hybridization days. The variance components included week-to-week, animal-to-animal and between-array and within-array variances.We applied the linear mixed-effects model to quantify different sources of variation. In the first data set, we found that the between-array variance is greater than the between-section variance, which, in turn, is greater than the within-section variance. In the second data set, for the reference samples, the week-to-week variance is larger than the between-array variance, which, in turn, is slightly larger than the within-array variance. For the test samples, the week-to-week variance has the largest variation. The animal-to-animal variance is slightly larger than the between-array and within-array variances. However, in a gene-by-gene analysis, the animal-to-animal variance is smaller than the between-array variance in four out of five housekeeping genes. In summary, the largest variation observed is the week-to-week effect. Another important source of variability is the animal-to-animal variation. Finally, we describe the use of variance-component estimates to determine optimal numbers of animals, arrays per animal and sections per array in planning microarray experiments.
Year
DOI
Venue
2004
10.1093/bioinformatics/bth118
Bioinformatics
Keywords
Field
DocType
variance component,nested within-array variance,largest variation,between-array variance,gene expression data,technical variance,week-to-week variance,animal-to-animal variance,within-array variance,between-section variance,within-section variance,mixed effects model,analysis of variance,housekeeping gene
Econometrics,Multivariate analysis of variance,Data set,One-way analysis of variance,Biology,Pooled variance,Bioinformatics,Statistics,Explained variation,Replicate,Analysis of variance,DNA microarray experiment
Journal
Volume
Issue
ISSN
20
9
1367-4803
Citations 
PageRank 
References 
14
1.31
1
Authors
8
Name
Order
Citations
PageRank
James J Chen143031.26
Robert R Delongchamp21537.23
Chen-An Tsai312311.12
Huey-Miin Hsueh4734.88
Frank Sistare5141.31
Karol L Thompson6441.93
Varsha G Desai7421.76
James C Fuscoe830015.86