title: Populus tremula (European aspen) shows no evidence of sexual dimorphism.
abstract: BACKGROUND
  Evolutionary theory suggests that males and females may evolve sexually dimorphic phenotypic and biochemical traits concordant with each sex having different optimal strategies of resource investment to maximise reproductive success and fitness. Such sexual dimorphism would result in sex biased gene expression patterns in non-floral organs for autosomal genes associated with the control and development of such phenotypic traits.
  
  
  RESULTS
  We examined morphological, biochemical and herbivory traits to test for sexually dimorphic resource allocation strategies within collections of sexually mature and immature Populus tremula (European aspen) trees. In addition we profiled gene expression in mature leaves of sexually mature wild trees using whole-genome oligonucleotide microarrays and RNA-Sequencing.
  
  
  CONCLUSIONS
  We found no evidence of sexual dimorphism or differential resource investment strategies between males and females in either sexually immature or mature trees. Similarly, single-gene differential expression and machine learning approaches revealed no evidence of large-scale sex biased gene expression. However, two significantly differentially expressed genes were identified from the RNA-Seq data, one of which is a robust diagnostic marker of sex in P. tremula.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Robinson
authors.forename: Nicolas
authors.initials: N
authors.lastname: Delhomme
authors.forename: Niklas
authors.initials: N
authors.lastname: Mähler
authors.forename: Bastian
authors.initials: B
authors.lastname: Schiffthaler
authors.forename: Jenny
authors.initials: J
authors.lastname: Onskog
authors.forename: Benedicte R
authors.initials: BR
authors.lastname: Albrectsen
authors.forename: Pär K
authors.initials: PK
authors.lastname: Ingvarsson
authors.forename: Torgeir R
authors.initials: TR
authors.lastname: Hvidsten
authors.forename: Stefan
authors.initials: S
authors.lastname: Jansson
authors.affiliation: Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, 901 87, Sweden. nathaniel.street@umu.se.
authors.forename: Nathaniel R
authors.initials: NR
authors.lastname: Street
mesh_terms: D018506:Gene Expression Regulation, Plant; D020411:Oligonucleotide Array Sequence Analysis; D018515:Plant Leaves / Q000235:genetics; D032107:Populus / Q000235:genetics* / Q000502:physiology; D017423:Sequence Analysis, RNA