Featured Research

from universities, journals, and other organizations

Turtle genome analysis sheds light on turtle ancestry and shell evolution

Date:
April 28, 2013
Source:
RIKEN
Summary:
From which ancestors have turtles evolved? How did they get their shell? New data provides evidence that turtles are not primitive reptiles but belong to a sister group of birds and crocodiles. The work also sheds light on the evolution of the turtle’s intriguing morphology and reveals that the turtle’s shell evolved by recruiting genetic information encoding for the limbs.

Turtle and chicken body plan during development.
Credit: Image courtesy of RIKEN

From which ancestors have turtles evolved? How did they get their shell? New data provided by the Joint International Turtle Genome Consortium, led by researchers from RIKEN in Japan, BGI in China, and the Wellcome Trust Sanger Institute in the UK provides evidence that turtles are not primitive reptiles but belong to a sister group of birds and crocodiles. The work also sheds light on the evolution of the turtle's intriguing morphology and reveals that the turtle's shell evolved by recruiting genetic information encoding for the limbs.

Related Articles


Turtles are often described as evolutionary monsters, with a unique body plan and a shell that is considered to be one of the most intriguing structures in the animal kingdom.

"Turtles are interesting because they offer an exceptional case to understand the big evolutionary changes that occurred in vertebrate history," explains Dr. Naoki Irie, from the RIKEN Center for Developmental Biology, who led the study.

Using next-generation DNA sequencers, the researchers from 9 international institutions have decoded the genome of the green sea turtle and Chinese soft-shell turtle and studied the expression of genetic information in the developing turtle.

Their results published in Nature Genetics show that turtles are not primitive reptiles as previously thought, but are related to the group comprising birds and crocodilians, which also includes extinct dinosaurs. Based on genomic information, the researchers predict that turtles must have split from this group around 250 million years ago, during one of the largest extinction events ever to take place on this planet.

"We expect that this research will motivate further work to elucidate the possible causal connection between these events," says Dr. Irie.

The study also reveals that despite their unique anatomy, turtles follow the basic embryonic pattern during development. Rather than developing directly into a turtle-specific body shape with a shell, they first establish the vertebrates' basic body plan and then enter a turtle-specific development phase. During this late specialization phase, the group found traces of limb-related gene expression in the embryonic shell, which indicates that the turtle shell evolved by recruiting part of the genetic program used for the limbs.

"The work not only provides insight into how turtles evolved, but also gives hints as to how the vertebrate developmental programs can be changed to produce major evolutionary novelties." explains Dr. Irie.

Another unexpected finding of the study was that turtles possess a large number of olfactory receptors and must therefore have the ability to smell a wide variety of substances. The researchers identified more than 1000 olfactory receptors in the soft-shell turtle, which is one of the largest numbers ever to be found in a non-mammalian vertebrate.


Story Source:

The above story is based on materials provided by RIKEN. Note: Materials may be edited for content and length.


Journal Reference:

  1. Zhuo Wang, Juan Pascual-Anaya, Amonida Zadissa, Wenqi Li, Yoshihito Niimura, Zhiyong Huang, Chunyi Li, Simon White, Zhiqiang Xiong, Dongming Fang, Bo Wang, Yao Ming, Yan Chen, Yuan Zheng, Shigehiro Kuraku, Miguel Pignatelli, Javier Herrero, Kathryn Beal, Masafumi Nozawa, Qiye Li, Juan Wang, Hongyan Zhang, Lili Yu, Shuji Shigenobu, Junyi Wang, Jiannan Liu, Paul Flicek, Steve Searle, Jun Wang, Shigeru Kuratani, Ye Yin, Bronwen Aken, Guojie Zhang, Naoki Irie. The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nature Genetics, 2013; DOI: 10.1038/ng.2615

Cite This Page:

RIKEN. "Turtle genome analysis sheds light on turtle ancestry and shell evolution." ScienceDaily. ScienceDaily, 28 April 2013. <www.sciencedaily.com/releases/2013/04/130428144848.htm>.
RIKEN. (2013, April 28). Turtle genome analysis sheds light on turtle ancestry and shell evolution. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2013/04/130428144848.htm
RIKEN. "Turtle genome analysis sheds light on turtle ancestry and shell evolution." ScienceDaily. www.sciencedaily.com/releases/2013/04/130428144848.htm (accessed October 31, 2014).

Share This



More Plants & Animals News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Surfer Accidentally Stands on Shark, Gets Bitten

Surfer Accidentally Stands on Shark, Gets Bitten

AP (Oct. 30, 2014) A 20-year-old competition surfer said on Thursday he accidentally stepped on a shark's head before it bit him off the Australian east coast. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Ebola Inflicts Heavy Toll on Guinean Potato Trade

Ebola Inflicts Heavy Toll on Guinean Potato Trade

AFP (Oct. 30, 2014) The Ebola epidemic has seen Senegal and Guinea Bissau close its borders with Guinea and the economic consequences have started to be felt, especially in Fouta Djallon, where the renowned potato industry has been hit hard. Duration: 02:01 Video provided by AFP
Powered by NewsLook.com
Genetically Altered Glowing Flower on Display in Tokyo

Genetically Altered Glowing Flower on Display in Tokyo

Reuters - Innovations Video Online (Oct. 30, 2014) Just in time for Halloween, a glowing flower goes on display in Tokyo. Instead of sorcery and magic, its creators used science to genetically modify the flower, adding a naturally fluorescent plankton protein to its genetic mix. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins