Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Turtle genome analysis sheds light on the development and evolution of turtle-specific body plan

29.04.2013
The latest study was published online in Nature Genetics

The Joint International Turtle Genomes Consortium, led by investigators from RIKEN, BGI, and Wellcome Trust Sanger Institute, has completed the genome sequencing of soft-shell turtle (Pelodiscus sinensis) and green sea turtle (Chelonia mydas). These achievements shed new light on the origin of turtles and applied the classical evo-devo model to explain the developmental process of their unique body plan. The findings were published online in Nature Genetics.

The evolution of turtles is an enigma in science. Their distinct body design-with a sharp beak and protective hard shell has changed very little over the past 210 million years. As the smallest species of soft-shell turtles, Chinese soft-shell turtle was once commonly sold in pet shops. Green sea turtle is considered as the largest of all the hard-shelled sea turtles and is named because of the green fat beneath its shell. Its population sizes has been drastically reduced recently and it has been listed as an endangered species.

To reveal the evolutionary history of turtles and the mechanisms underlying the development of their unique anatomical features, researchers in this project sequenced and analyzed the genomes of soft-shell turtle and green sea turtle. They found the evidence that turtles are likely to be a sister group with the common ancestor of crocodilians and birds from whole genome phylogenetic analyses. The turtles were diverged from archosaurians approximately between 267.9 and 248.3 million years ago, which coincides with the time range of the Upper Permian to Triassic period that overlapped or followed shortly after the end of Permian extinction.

In the study, researchers performed the brief research on genes may be associated with the turtle-specific characteristics, and found some olfactory receptor (OR) gene families were highly expanded in both turtles. This finding suggests that turtles have developed superior olfaction ability against a wide variety of hydrophilic substances. In addition, many genes involved in taste perception, hunger-stimulating, and energy homeostasis regulating hormone ghrelin have been uniquely lost in turtles. Researchers suggested that the loss of these genes may be related to their low-metabolic rate.

The consortium also investigated the association of embryonic gene expression profiles (GXP) and their morphological evolution pattern, based on ENSEMBL soft-shell turtle gene-set. By integrating RNA-seq technology, comparative genomics method, and mathematical statistical approaches, researchers confirmed GXP divergence during embryogenesis of soft-shell turtle and chicken indeed follows the developmental hourglass model. They also revealed that the maximal conservation stage occurred at around the vertebrate phylotypic period, rather than at later stage that show the amniote-common pattern.

To clarify the morphological specifications of turtle embryogenesis in late development, especially the formation of the carapacial ridge (CR), researchers investigated into CR-specific miRNA expression, found existence of tissue-specific miRNAs and involvement of Wnt signaling. Also they revealed the Wnt expression involved in the carapacial ridge (CR) formation of the turtle shell, researchers annotated all the Wnt genes in the two turtle genomes, identifying a total of 20 Wnt genes. Intriguingly, they discovered Wnt5a is the only Wnt gene expressed in the turtle CR region, supporting the possible co-option of limb-associated Wnt signaling in the acquisition of this turtle-specific novelty.

Zhuo Wang, Project Manager from BGI, said, "The genome-wide phylogenetic analysis of two turtles in our project, along with two crocodile genomic data additionally, makes clear the evolutionary history of turtles in diverging from other species and settles the disputes about the phylogenetic position of reptiles. The genomic analyses and embryonic gene expression profiles have been combined to reveal the fundamental evo-devo questions on turtle evolution and development. These works have been highly appreciated by the editor and reviewers. Besides the interesting story, the genomic data we released here will provide a platform for more scientists to initialize their genome-wide studies on turtles. "

Dr. Hongyan Zhang, Regional Director of BGI Tech Solutions Co., Ltd. for Japan, said, "The completed genome sequencing of soft-shell turtle and green sea turtle give an important hint to uncover the development and evolution mechanism of turtles. This scientific achievement is a joint effort supported by BGI's advanced sequencing technologies and excellent bioinformatics capabilities, the profound basis research background of developmental biology from RIKEN, and other partners' great contributions. We are looking forward to having more collaboration with other scientists for better exploring the secret of life together in the near future."

About BGI

BGI was founded in 1999 with the mission of being a premier scientific partner to the global research community. The goal of BGI is to make leading-edge genomic science highly accessible through its investment in infrastructure that leverages the best available technology, economies of scale, and expert bioinformatics resources. BGI, which includes both private non-profit genomic research institutes and sequencing application commercial units, and its affiliates, BGI Americas, headquartered in Cambridge, MA, and BGI Europe, headquartered in Copenhagen, Denmark, have established partnerships and collaborations with leading academic and government research institutions as well as global biotechnology and pharmaceutical companies, supporting a variety of disease, agricultural, environmental, and related applications. BGI has established a proven track record of excellence, delivering results with high efficiency and accuracy for innovative, high-profile research which has generated over 250 publications in top-tier journals such as Nature and Science. These accomplishments include sequencing one percent of the human genome for the International Human Genome Project, contributing 10 percent to the International Human HapMap Project, carrying out research to combat SARS and German deadly E. coli, playing a key role in the Sino-British Chicken Genome Project, and completing the sequence of the rice genome, the silkworm genome, the first Asian diploid genome, the potato genome, and, most recently, have sequenced the human Gut metagenome, and a significant proportion of the genomes for the 1,000 genomes project. For more information about BGI please visit http://www.genomics.cn

Further information

Bicheng Yang
Public Communications Officer, BGI, Tel: +86-755-82639701 or Email: yangbicheng@genomics.cn

Jia Liu | EurekAlert!
Further information:
http://www.genomics.cn

More articles from Life Sciences:

nachricht Glycosylation: Mapping Uncharted Territory
21.09.2017 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

nachricht Molecular Force Sensors
20.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Glycosylation: Mapping Uncharted Territory

21.09.2017 | Life Sciences

Highly precise wiring in the Cerebral Cortex

21.09.2017 | Health and Medicine

Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?

21.09.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>