title: Microarray expression profiles of 20.000 genes across 23 healthy porcine tissues.
abstract: BACKGROUND
  Gene expression microarrays have been intensively applied to screen for genes involved in specific biological processes of interest such as diseases or responses to environmental stimuli. For mammalian species, cataloging of the global gene expression profiles in large tissue collections under normal conditions have been focusing on human and mouse genomes but is lacking for the pig genome.
  
  
  RESULTS
  Here we present the results from a large-scale porcine study establishing microarray cDNA expression profiles of approximately 20.000 genes across 23 healthy tissues. As expected, a large portion of the genes show tissue specific expression in agreement with mappings to gene descriptions, Gene Ontology terms and KEGG pathways. Two-way hierarchical clustering identified expected tissue clusters in accordance with tissue type and a number of cDNA clusters having similar gene expression patterns across tissues. For one of these cDNA clusters, we demonstrate that possible tissue associated gene function can be inferred for previously uncharacterized genes based on their shared expression patterns with functionally annotated genes. We show that gene expression in common porcine tissues is similar to the expression in homologous tissues of human.
  
  
  CONCLUSIONS
  The results from this study constitute a valuable and publicly available resource of basic gene expression profiles in normal porcine tissues and will contribute to the identification and functional annotation of porcine genes.
authors.affiliation: Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Tjele, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Hornshøj
authors.forename: Lene Nagstrup
authors.initials: LN
authors.lastname: Conley
authors.forename: Jakob
authors.initials: J
authors.lastname: Hedegaard
authors.forename: Peter
authors.initials: P
authors.lastname: Sørensen
authors.forename: Frank
authors.initials: F
authors.lastname: Panitz
authors.forename: Christian
authors.initials: C
authors.lastname: Bendixen
mesh_terms: D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D013552:Swine
chemical_list: D018076:DNA, Complementary