title: Next generation sequencing and analysis of a conserved transcriptome of New Zealand's kiwi.
abstract: BACKGROUND
  Kiwi is a highly distinctive, flightless and endangered ratite bird endemic to New Zealand. To understand the patterns of molecular evolution of the nuclear protein-coding genes in brown kiwi (Apteryx australis mantelli) and to determine the timescale of avian history we sequenced a transcriptome obtained from a kiwi embryo using next generation sequencing methods. We then assembled the conserved protein-coding regions using the chicken proteome as a scaffold.
  
  
  RESULTS
  Using 1,543 conserved protein coding genes we estimated the neutral evolutionary divergence between the kiwi and chicken to be ~45%, which is approximately equal to the divergence computed for the human-mouse pair using the same set of genes. A large fraction of genes was found to be under high selective constraint, as most of the expressed genes appeared to be involved in developmental gene regulation. Our study suggests a significant relationship between gene expression levels and protein evolution. Using sequences from over 700 nuclear genes we estimated the divergence between the two basal avian groups, Palaeognathae and Neognathae to be 132 million years, which is consistent with previous studies using mitochondrial genes.
  
  
  CONCLUSIONS
  The results of this investigation revealed patterns of mutation and purifying selection in conserved protein coding regions in birds. Furthermore this study suggests a relatively cost-effective way of obtaining a glimpse into the fundamental molecular evolutionary attributes of a genome, particularly when no closely related genomic sequence is available.
authors.affiliation: Griffith School of Environment and the School of Biomolecular and Physical Sciences, Griffith University, 170 Kessels Road, Nathan, Qld 4111 Australia.
authors.forename: Sankar
authors.initials: S
authors.lastname: Subramanian
authors.forename: Leon
authors.initials: L
authors.lastname: Huynen
authors.forename: Craig D
authors.initials: CD
authors.lastname: Millar
authors.forename: David M
authors.initials: DM
authors.lastname: Lambert
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D017124:Conserved Sequence; D019143:Evolution, Molecular; D018628:Gene Dosage; D020869:Gene Expression Profiling; D015723:Gene Library; D006801:Humans; D008297:Male; D051379:Mice; D009520:New Zealand; D046108:Palaeognathae / Q000145:classification / Q000235:genetics*; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA