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Background
“We describe the genome of the western painted turtle, Chrysemys picta bellii, one of the most widespread, abundant and well-studied turtles. We place the genome into a comparative evolutionary context, and focus on genomic features associated with tooth loss, immune function, longevity, sex differentiation and determination, and the species? physiological capacities to withstand extreme anoxia and tissue freezing.
Results
Our phylogenetic analyses confirm that turtles are the sister group to living archosaurs, and demonstrate an extraordinarily slow rate of sequence evolution in the painted turtle. The ability of the painted turtle to withstand complete anoxia and partial freezing appears to be associated with common vertebrate gene networks, and we identify candidate genes for future functional analyses. Tooth loss shares a common pattern of pseudogenization and degradation of tooth-specific genes with birds, although the rate of accumulation of mutations is much slower in the painted turtle. Genes associated with sex differentiation generally reflect phylogeny rather than convergence in sex determination functionality. Among gene families that demonstrate exceptional expansions or show signatures of strong natural selection, immune function and musculoskeletal patterning genes are consistently overrepresented.
Conclusions
Our comparative genomic analyses indicate that common vertebrate regulatory networks, some of which have analogs in human diseases, are often involved in the western painted turtle?s extraordinary physiological capacities. As these regulatory pathways are analyzed at the functional level, the painted turtle may offer important insights into the management of a number of human health disorders.”
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Turtle (top view) (May 1852) by The Ernst Mayr Library on Flickr.
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Chitra indica - Indian narrow-headed softshell turtle - by BioDivLibrary on Flickr.
Catalogue of shield reptiles in the collection of the British Museum /.
London :Printed by order of the Trustees,1855-1872..
biodiversitylibrary.org/page/4388547 -
The skull of Macrochelys temminckii - alligator snapping turtle by BioDivLibrary on Flickr.
Catalogue of shield reptiles in the collection of the British Museum /.
London :Printed by order of the Trustees,1855-1872..
biodiversitylibrary.org/page/4388543 -
Chelonia (mydas) virgata, Schweiger, vulg. Carey. (1838-1857)
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Skulls of Macrochelys temminckii (alligator snapping turtle) and Chelydra serpentina (common snapping turtle) by BioDivLibrary on Flickr.
Catalogue of shield reptiles in the collection of the British Museum /.
London :Printed by order of the Trustees,1855-1872..
biodiversitylibrary.org/page/4388545 -
Catalogue of shield reptiles in the collection of the British Museum by BioDivLibrary on Flickr.
London :Printed by order of the Trustees,1855-1872..
biodiversitylibrary.org/page/4388535 -
Archelon - a giant sea turtle from the Late Cretaceous
Source: Water reptiles of the past and present, by Samuel Wendell Williston
See also:
The osteology of Protostega by G.R. Wieland
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I figured I’ll slowly put up some of these old animal drawings of mine.
This is an Eastern Box turtle, a resident I find at my house from time to time. They used to be very common in this area, but with habitat loss due to human population and farming land, they’re now very rare. I’m lucky to see more than a dozen a year as opposed to a few decades ago when my parents would see them almost daily.
Their brightly colored shells help them blend in with leaf litter as they go foraging for anything from insects to fruits. They are very long lived, and for a long time, we would be able to see resident turtles and recognize them by the patterns on their shells, or by old healed over injuries that made them easy to spot.
This was drawn in 2006, with markers.
