Phylogenetic Origins of Brain Organisers
Joint Authors
Kiecker, Clemens
Robertshaw, Ellen
Source
Issue
Vol. 2012, Issue 2012 (31 Dec. 2012), pp.1-14, 14 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2012-07-24
Country of Publication
Egypt
No. of Pages
14
Main Subjects
Natural & Life Sciences (Multidisciplinary)
Diseases
Abstract EN
The regionalisation of the nervous system begins early in embryogenesis, concomitant with the establishment of the anteroposterior (AP) and dorsoventral (DV) body axes.
The molecular mechanisms that drive axis induction appear to be conserved throughout the animal kingdom and may be phylogenetically older than the emergence of bilateral symmetry.
As a result of this process, groups of patterning genes that are equally well conserved are expressed at specific AP and DV coordinates of the embryo.
In the emerging nervous system of vertebrate embryos, this initial pattern is refined by local signalling centres, secondary organisers, that regulate patterning, proliferation, and axonal pathfinding in adjacent neuroepithelium.
The main secondary organisers for the AP neuraxis are the midbrain-hindbrain boundary, zona limitans intrathalamica, and anterior neural ridge and for the DV neuraxis the notochord, floor plate, and roof plate.
A search for homologous secondary organisers in nonvertebrate lineages has led to controversy over their phylogenetic origins.
Based on a recent study in hemichordates, it has been suggested that the AP secondary organisers evolved at the base of the deuterostome superphylum, earlier than previously thought.
According to this view, the lack of signalling centres in some deuterostome lineages is likely to reflect a secondary loss due to adaptive processes.
We propose that the relative evolutionary flexibility of secondary organisers has contributed to a broader morphological complexity of nervous systems in different clades.
American Psychological Association (APA)
Robertshaw, Ellen& Kiecker, Clemens. 2012. Phylogenetic Origins of Brain Organisers. Scientifica،Vol. 2012, no. 2012, pp.1-14.
https://search.emarefa.net/detail/BIM-474480
Modern Language Association (MLA)
Robertshaw, Ellen& Kiecker, Clemens. Phylogenetic Origins of Brain Organisers. Scientifica No. 2012 (2012), pp.1-14.
https://search.emarefa.net/detail/BIM-474480
American Medical Association (AMA)
Robertshaw, Ellen& Kiecker, Clemens. Phylogenetic Origins of Brain Organisers. Scientifica. 2012. Vol. 2012, no. 2012, pp.1-14.
https://search.emarefa.net/detail/BIM-474480
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-474480