Mining for Low-abundance Transcripts in Microarray Data

• differential gene expression using mRNA chips – diabetes and obesity study (biochemistry) • lean vs. obese mice: how do they differ? • what is the role of genetic background? – detecting genes at low expression levels • inference issues – formal evaluation of each gene with(out) replication • smoothly combine information across genes – significance level and multiple comparisons – general pattern recognition: tradeoffs of false +/– • modelling differential expression – gene-specific vs. dependence on abundance – R software module