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 Polymers Based on Boron?
18.01.2018 | Julius-Maximilians-Universität Würzburg

nachricht Bioengineered soft microfibers improve T-cell production
18.01.2018 | Columbia University School of Engineering and Applied Science

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Polymers Based on Boron?

18.01.2018 | Life Sciences

Bioengineered soft microfibers improve T-cell production

18.01.2018 | Life Sciences

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>