title: Transcriptome analysis reveals novel patterning and pigmentation genes underlying Heliconius butterfly wing pattern variation.
abstract: BACKGROUND
  Heliconius butterfly wing pattern diversity offers a unique opportunity to investigate how natural genetic variation can drive the evolution of complex adaptive phenotypes. Positional cloning and candidate gene studies have identified a handful of regulatory and pigmentation genes implicated in Heliconius wing pattern variation, but little is known about the greater developmental networks within which these genes interact to pattern a wing. Here we took a large-scale transcriptomic approach to identify the network of genes involved in Heliconius wing pattern development and variation. This included applying over 140 transcriptome microarrays to assay gene expression in dissected wing pattern elements across a range of developmental stages and wing pattern morphs of Heliconius erato.
  
  
  RESULTS
  We identified a number of putative early prepattern genes with color-pattern related expression domains. We also identified 51 genes differentially expressed in association with natural color pattern variation. Of these, the previously identified color pattern "switch gene" optix was recovered as the first transcript to show color-specific differential expression. Most differentially expressed genes were transcribed late in pupal development and have roles in cuticle formation or pigment synthesis. These include previously undescribed transporter genes associated with ommochrome pigmentation. Furthermore, we observed upregulation of melanin-repressing genes such as ebony and Dat1 in non-melanic patterns.
  
  
  CONCLUSIONS
  This study identifies many new genes implicated in butterfly wing pattern development and provides a glimpse into the number and types of genes affected by variation in genes that drive color pattern evolution.
authors: Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA. hmh19@psu.edu
authors: Heather M
authors: HM
authors: Hines
authors: Riccardo
authors: R
authors: Papa
authors: Mayte
authors: M
authors: Ruiz
authors: Alexie
authors: A
authors: Papanicolaou
authors: Charles
authors: C
authors: Wang
authors: H Frederik
authors: HF
authors: Nijhout
authors: W Owen
authors: WO
authors: McMillan
authors: Robert D
authors: RD
authors: Reed
mesh_terms: D000818:Animals; D002080:Butterflies / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism; D020869:Gene Expression Profiling; D014644:Genetic Variation; D023281:Genomics; D008543:Melanins / Q000378:metabolism; D010640:Phenothiazines / Q000378:metabolism; D010858:Pigmentation / Q000235:genetics*; D014921:Wings, Animal / Q000378:metabolism
chemical_list: D004798:Enzymes; D008543:Melanins; D010640:Phenothiazines; C002772:ommochrome