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.
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 informationBicheng Yang
Jia Liu | EurekAlert!
Enduring cold temperatures alters fat cell epigenetics
19.04.2018 | University of Tokyo
Full of hot air and proud of it
18.04.2018 | University of Pittsburgh
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy