Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs.

Journal Article

To provide context for the diversification of archosaurs--the group that includes crocodilians, dinosaurs, and birds--we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the comparatively rapid evolution is derived in birds. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs, thereby providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs.

Full Text

Duke Authors

Cited Authors

  • Green, RE; Braun, EL; Armstrong, J; Earl, D; Nguyen, N; Hickey, G; Vandewege, MW; St John, JA; Capella-Gutiérrez, S; Castoe, TA; Kern, C; Fujita, MK; Opazo, JC; Jurka, J; Kojima, KK; Caballero, J; Hubley, RM; Smit, AF; Platt, RN; Lavoie, CA; Ramakodi, MP; Finger, JW; Suh, A; Isberg, SR; Miles, L; Chong, AY; Jaratlerdsiri, W; Gongora, J; Moran, C; Iriarte, A; McCormack, J; Burgess, SC; Edwards, SV; Lyons, E; Williams, C; Breen, M; Howard, JT; Gresham, CR; Peterson, DG; Schmitz, J; Pollock, DD et al.

Published Date

  • December 11, 2014

Published In

Volume / Issue

  • 346 / 6215

Start / End Page

  • 1254449 -

PubMed ID

  • 25504731

Electronic International Standard Serial Number (EISSN)

  • 1095-9203

International Standard Serial Number (ISSN)

  • 0036-8075

Digital Object Identifier (DOI)

  • 10.1126/science.1254449

Language

  • eng