Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Measuring evolution’s waistline

06.06.2011
Gene expression data offer surprising evidence that embryos of different vertebrate species are most similar at intermediate stages of development

Nearly 150 years ago, noted German biologist Ernst Haeckel made the bold assertion that ‘ontogeny recapitulates phylogeny’: in other words, morphological changes that occur during an organism’s embryonic development mirror its evolutionary history.

This concept has long since been debunked, but has nevertheless provided useful starting points for considering the yet-unsolved question of how the developmental process has evolved. Naoki Irie of the RIKEN Center for Developmental Biology (CDB) in Kobe has pondered this problem since graduate school. “My main interest then and now has been to understand the basic or common rules of how animal bodies develop,” he says.

Now, as a postdoctoral fellow in Shigeru Kuratani’s laboratory at CDB, Irie has conducted an ambitious comparative analysis of four vertebrate species with the aim of resolving an ongoing debate over two prevailing evolutionary models1. The ‘funnel-like’ model, informed in part by Haeckel’s thinking, suggests that the process of vertebrate embryonic development is very similar across species at the earliest stages, but increasingly differs at later stages. In contrast, the ‘hourglass’ model suggests that the earliest and latest stages of development differ considerably, whereas the greatest similarity is observed at the intermediate stages where organ development and body patterning take place.

To resolve this so-called ‘evo-devo’ debate, Irie and Kuratani analyzed changes in expression levels of thousands of evolutionarily conserved genes at different developmental points in the mouse, chicken, frog and zebrafish. The data provided striking support for the hourglass model, with gene transcription levels most similar at the intermediate stage known as ‘pharyngula’, where the animal has developed primitive precursors of the heart, kidney, brain and other tissues. They observed particularly strong conservation of activity among the Hox genes, which contribute to limb development, as well as several growth factor genes.

These findings offer new fuel for the evo-devo debate, but also raise complicated questions. “It is puzzling for me how vertebrate embryos established differences in early developmental stages while conserving the mid-embryonic stages,” says Irie. “It’s obvious that later developmental stages will not exist if earlier stages fail to develop successfully.”

Irie now hopes to obtain further support for the hourglass model by expanding his approach to include well-characterized invertebrate species, such as the fruit fly. He also intends to dig deeper into the nuts and bolts of development. “We would like to go down to the level of tissues and primordial organs to find which structures have been conserved during evolution,” he says.

The corresponding author for this highlight is based at the Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology

Journal information

[1] Irie, N. & Kuratani, S. Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis. Nature Communications 2, 248 (2011)

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

More articles from Life Sciences:

nachricht Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

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...

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

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>