Turtles are related to BIRDS: 'Tree of life' genetic sequencing reveals reptiles' distant and unexpected relatives
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Turtles may look like the hard-shelled relatives of lizards and snakes, but their DNA suggests they have far more in common with birds.
This is according to US scientists who used a new genetic sequencing technique called Ultra Conserved Elements (UCE) to finally settle the debate on turtle evolution.
The results, they say, reveal that turtles belong to a large group called 'Archelosauria,' along with their relatives birds, crocodiles and dinosaurs.
Turtles may look like the hard-shelled relatives of lizards and snakes, but their DNA suggests they have far more in common with birds
Scientists at the California Academy of Sciences suspect the new group will be the largest group of vertebrates to ever receive a new scientific name.
Their 'tree of life' is consistent with the time and space patterns in which turtle species appear in the fossil record, highlighting the accuracy of the method.
Although UCE has been available for two years, this is the first time the scientists have used the tool to genetically map vertebrates and how they are related.
It works by analysing parts of the genome that are highly conserved between different species.
The findings also resolve an evolutionary mystery surrounding soft-shell turtles (pictured)- a bizarre group of scale-less turtles with snorkel-like snouts. Until now, studies linked softshell turtles with a smaller semi-aquatic group called mud turtles
'Calling this is an exciting new era of sequencing technology is an understatement,' says Brian Simison, PhD, Director of the Academy's Center for Comparative Genomics (CCG).
'In the space of just five years, reasonably affordable studies using DNA sequencing have advanced from using only a handful of genetic markers to more than 2,000 - an unbelievable amount of DNA.
'New techniques like UCE dramatically improve our ability to help resolve decades-long evolutionary mysteries, giving us a clear picture of how animals like turtles evolved on our constantly-changing planet.'
The findings also resolve an evolutionary mystery surrounding soft-shell turtles - a bizarre group of scale-less turtles with snorkel-like snouts.
Until now, studies linked softshell turtles with a smaller semi-aquatic group called mud turtles, despite the fact that softshells appear in the fossil record long before their mud-loving counterparts.
The Academy's study places softshells in a league of their own on the evolutionary tree, quite far removed from any turtle relatives.
Their long independent history helps explain their striking looks as well as their ancient presence in the fossil record.
With large amounts of data backing up each evolutionary branch on the turtle tree of life, scientists are able to compare their evolution not only across species, but also across each continent's corresponding fossil records.
'I have been working on the evolutionary relationships of turtles for over 20 years using a variety of methods,' said Dr Parham.
'Fossils are essential for showing us what extinct turtles looked like, but also in letting us know when and where they lived in the past.'
The results reveal that turtles belong to a large group called 'Archelosauria,' along with their relatives birds, crocodiles and dinosaurs, such as T.Rex (pictured)
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