Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs.
Abstract
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.
Type
Journal articleSubject
Alligators and CrocodilesAnimals
Biological Evolution
Birds
Conserved Sequence
DNA Transposable Elements
Dinosaurs
Evolution, Molecular
Genetic Variation
Genome
Molecular Sequence Annotation
Molecular Sequence Data
Phylogeny
Reptiles
Sequence Alignment
Sequence Analysis, DNA
Transcriptome
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https://hdl.handle.net/10161/11153Published Version (Please cite this version)
10.1126/science.1254449Publication Info
Green, Richard E; Braun, Edward L; Armstrong, Joel; Earl, Dent; Nguyen, Ngan; Hickey,
Glenn; ... Ray, David A (2014). Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs.
Science, 346(6215). pp. 1254449. 10.1126/science.1254449. Retrieved from https://hdl.handle.net/10161/11153.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Erich David Jarvis
Adjunct Professor in the Deptartment of Neurobiology
Dr. Jarvis' laboratory studies the neurobiology of vocal communication. Emphasis is
placed on the molecular pathways involved in the perception and production of learned
vocalizations. They use an integrative approach that combines behavioral, anatomical,
electrophysiological and molecular biological techniques. The main animal model used
is songbirds, one of the few vertebrate groups that evolved the ability to learn vocalizations.
The generality of the discoveries is tested in other vocal lear

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