Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Transcriptomic insights into the vertebrate phylotypic stage

18.05.2011
A new comparative transcriptomic analysis of four vertebrate species conducted by Naoki Irie in RIKEN's Laboratory for Evolutionary Morphology strongly suggests that the 'hourglass model' is the more accurate description of how the vertebrate phylotype manifests.

The concept of the phylotypic stage traces its roots back to early comparative observations of embryos from different vertebrate taxa, in which it was noted that embryonic morphologies appeared to converge on a shared body plan before veering off in specialized directions.

This gave rise to a profound debate over the evolutionary basis for this phenomenon; specifically, whether it could best be explained by a “funnel” model, in which the commonality of traits is highest at the earliest stages of embryogenesis, and gradually but unilaterally narrows over time, or an “hourglass” model, where homology is highest at a point later in development as the body plan is being established, and differs more widely before and after.

A new comparative transcriptomic analysis of four vertebrate species conducted by Naoki Irie in the Laboratory for Evolutionary Morphology (Shigeru Kuratani, Group Director) has now revealed that genetic expression is most highly conserved across taxa at the pharyngula stage of development. Published in Nature Communications, these latest findings strongly suggest that the hourglass model is the more accurate description of how the vertebrate phylotype manifests.

Irie decision to study this question using a gene expression approach broke with the long history of morphological comparisons. He sampled tissue from mouse, chicken, and frog embryos across multiple developmental stages to allow for comparisons of changes in gene expression, and further supplemented this data set with information from previously published transcriptomic studies in a fourth taxa, zebrafish, thus providing representative samples from mammal, bird, amphibian and fish species. He took advantage of the supercomputing capabilities at the RIKEN integrated Cluster of Clusters (RICC) for the processing power needed for comparison of this enormous set of data points.

As development proceeds at different paces in different species, and organs likewise emerge at different points, making straightforward comparisons can be extremely problematic. To overcome this challenge, Irie selected genes homologous in all four species, and made pairwise comparisons of gene expression profiles by microarray analyses. For each pairing, he found that the highest similarity was seen in intermediate stages of embryogenesis (from neurula to late pharyngula stages). More sophisticated computational analysis revealed that pharyngular embryos had the highest transcriptomic similarity of any stage.

To ascertain the detailed molecular characteristics of this phylotypic stage, the group went on to identify genes showing conserved expression during the pharyngula stage, but that were not constitutively expressed throughout embryogenesis, and identified 109 gene sets, including Hox genes, transcription factors, cell-cell signaling genes, and morphogens. Interestingly, within these sets, developmental genes were more highly represented than in sets with different expression profiles. The data generated in this study has been deposited in the ArrayExpress and Gene Expression Omnibus repositories.

“It seems that the notion that genetic programs underlying early development are resistant to change needs to be reconsidered in light of this data,” says Irie. “We’ll be interested in working out how early genetic flexibility is achieved while maintaining the robustness of gene expression at the phylotypic pharyngula stage.”

For more information, contact:

Douglas Sipp : sipp(at)cdb.riken.jp
TEL : +81-78-306-3043
RIKEN CDB, Office for Science Communications and International Affairs

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht During HIV infection, antibody can block B cells from fighting pathogens
14.08.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht First study on physical properties of giant cancer cells may inform new treatments
14.08.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>