The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan

Nat Genet. 2013 Jun;45(6):701-706. doi: 10.1038/ng.2615. Epub 2013 Apr 28.


The unique anatomical features of turtles have raised unanswered questions about the origin of their unique body plan. We generated and analyzed draft genomes of the soft-shell turtle (Pelodiscus sinensis) and the green sea turtle (Chelonia mydas); our results indicated the close relationship of the turtles to the bird-crocodilian lineage, from which they split ∼267.9-248.3 million years ago (Upper Permian to Triassic). We also found extensive expansion of olfactory receptor genes in these turtles. Embryonic gene expression analysis identified an hourglass-like divergence of turtle and chicken embryogenesis, with maximal conservation around the vertebrate phylotypic period, rather than at later stages that show the amniote-common pattern. Wnt5a expression was found in the growth zone of the dorsal shell, supporting the possible co-option of limb-associated Wnt signaling in the acquisition of this turtle-specific novelty. Our results suggest that turtle evolution was accompanied by an unexpectedly conservative vertebrate phylotypic period, followed by turtle-specific repatterning of development to yield the novel structure of the shell.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Shells / metabolism
  • Animals
  • Body Patterning / genetics
  • Chick Embryo
  • Chickens / genetics
  • Embryonic Development / genetics
  • Evolution, Molecular
  • Gene Expression Regulation, Developmental
  • Genome
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Molecular Sequence Annotation
  • Molecular Sequence Data
  • Phylogeny
  • Receptors, Odorant / genetics
  • Reptilian Proteins / genetics
  • Reptilian Proteins / metabolism
  • Sequence Analysis, DNA
  • Transcriptome
  • Turtles / embryology
  • Turtles / genetics*
  • Wnt Proteins / genetics
  • Wnt Proteins / metabolism


  • MicroRNAs
  • Receptors, Odorant
  • Reptilian Proteins
  • Wnt Proteins

Associated data

  • GENBANK/JQ968433
  • GENBANK/JQ968452