Navigation Links
The Origin of the Brain Lies in a Worm

The rise of the central nervous system [CNS] in animal evolution has puzzled scientists for centuries. Vertebrates, insects and worms evolved// from the same ancestor, but their CNSs are different and were thought to have evolved only after their lineages had split during evolution. Researchers from the European Molecular Biology Laboratory [EMBL] in Heidelberg now reveal that the vertebrate nervous system is probably much older than expected. The study, which is published in the current issue of Cell, suggests that the last common ancestor of vertebrates, insects and worms already had a centralised nervous system resembling that of vertebrates today.

Many animals have evolved complex nervous systems throughout the course of evolution, but their architectures can differ substantially between species. While vertebrates have a CNS in the shape of a spinal cord running along their backs, insects and annelid worms like the earthworm have a rope-ladder-like chain of nerve cell clusters on their belly side. Other invertebrates on the other hand have their nerve cells distributed diffusely over their body. Yet, all these species descend from a common ancestor called Urbilateria. If this ancestor already possessed a nervous system, what it might have looked like and how it gave rise to the diversity of nervous systems seen in animals today is what Detlev Arendt and his group study at EMBL. To do so, they investigate the nervous system of a marine annelid worm called Platynereis dumerilii. "Platynereis can be considered a living fossil," says Arendt, "it still lives in the same environment as the last common ancestors used to and has preserved many ancestral features, including a prototype invertebrate CNS."

Arendt and his group investigated how the developing CNS in Platynereis embryos gets subdivided into the regions that later on give rise to the different CNS structures. The regions are defined by the unique combination of regulatory genes expressed, which endow every type of neuron with a specific molecular fingerprint. Comparing the molecular fingerpint of Platynereis nerve cells with what is known about vertebrates revealed surprising similarities.

"Our findings were overwhelming," says Alexandru Denes, who carried out the research in Arendt's lab. "The molecular anatomy of the developing CNS turned out to be virtually the same in vertebrates and Platynereis. Corresponding regions give rise to neuron types with similar molecular fingerprints and these neurons also go on to form the same neural structures in annelid worm and vertebrate."

"Such a complex arrangement could not have been invented twice throughout evolution, it must be the same system," adds Gáspár Jékely, a researcher from Arendt's lab, who contributed essentially to the study. "It looks like Platynereis and vertebrates have inherited the organisation of their CNS from their remote common ancestors."

The findings provide strong evidence for a theory that was first put forward by zoologist Anton Dohrn in 1875. It states that vertebrate and annelid CNS are of common descent and vertebrates have turned themselves upside down throughout the course of evolution.

"This explains perfectly why we find the same centralised CNS on the backside of vertebrates and the bellyside of Platynereis," Arendt says. "How the inversion occurred and how other invertebrates have modified the ancestral CNS throughout evolution are the next exciting questions for evolutionary biologists."

Source-Eurekalert
'"/>




Related medicine news :

1. Origin Of SARS Virus Discovered
2. Understanding The Origin Of Tumors
3. Developmental Origins of Polycystic Ovarian Syndrome
4. Mice Aids in Shedding Light on Origin of Autism
5. Origin of HIV Traced To Wild Chimps
6. Origin of obesity may be in brain: scientists
7. Indian Origin Woman is the New Head of British Medical Association
8. Researcher Reports on Origin of Deadly Fever Outbreak
9. Indian Origin Doctor Faces Trial for Cheating
10. Team Tracks Genetic Origins of Eye Cancer
11. Origin Of Sex Can Be Revealed By Sperm Proteome
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/26/2016)... ... June 26, 2016 , ... On June 10-11, 2016, A Forever Recovery, a ... and World’s Longest Breakfast Table in Battle Creek, MI, where the rehabilitation facility is ... to some of the world’s leading providers of cereal and other breakfast foods. Its ...
(Date:6/26/2016)... ... June 26, 2016 , ... PawPaws brand pet supplements owned by ... to enhance the health of felines. The formula is all-natural and is made from ... the PawPaws Cat Kidney Support Supplement Soft Chews are Astragalus Root Extract ...
(Date:6/26/2016)... Orion, Clarkston, Michigan (PRWEB) , ... June 26, ... ... with respect to fertility once they have been diagnosed with endometriosis. These women ... intercourse but they also require a comprehensive approach that can help for preservation ...
(Date:6/25/2016)... TX (PRWEB) , ... June 25, 2016 , ... Austin ... of the American College of Mohs Surgery and to Dr. Russell Peckham for medical ... and highly effective treatment for skin cancer. The selective fellowship in Mohs Micrographic Surgery ...
(Date:6/25/2016)... Aliso Viejo, California (PRWEB) , ... June 25, 2016 , ... ... preset to fit their specific project," said Christina Austin - CEO of Pixel Film ... all fully customizable and all within Final Cut Pro X . Simply select ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... Ill. , June 23, 2016  In a startling report ... are failing their residents by lacking a comprehensive, proven plan to ... a definitive ranking of how states are tackling the worst ... to only four states – Kentucky , ... Vermont . Of the 28 failing states, three ...
(Date:6/23/2016)... -- Bracket , a leading clinical trial technology and ... platform, Bracket eCOA (SM) 6.0, at the 52 nd ... 2016 in Philadelphia , Pennsylvania.  A demonstration ... of its kind to fully integrate with RTSM, will be ... is a flexible platform for electronic clinical outcomes assessments that ...
(Date:6/23/2016)... 23, 2016  Guerbet announced today that it has ... Horizon Award . One of 12 suppliers ... for its support of Premier members through exceptional local ... and commitment to lower costs. ... of our outstanding customer service from Premier," says ...
Breaking Medicine Technology: