Echinoderm Nervous System Evolution Project

## Introduction

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The broad objective of this project is to help understand the homology of the urbilaterian nervous system, a question that has puzzled researchers for more than a century. Modern tools and techniques offer new ways of searching for missing pieces to this puzzle. This research focuses on the origin of cell types in the echinoderm nervous system as compared to the nervous system of other Bilateria and Eumetazoa, a promising avenue of exploration that may elucidate aspects of homology not apparent from developmental and gene-expression studies.[1][2]

Echinoderms are of particular interest because their pentaradial (five-fold) symmetry is so enigmatic. It is likely that, at an early stage in their evolutionary history, they lost their cephalic ganglion. One class, Holothuroidea (sea cucumbers) has regained a cephalic ganglion. The unusual echinoderm body shape may have evolved from the translocation and inversion of the gene segment containing Hox1-Hox3, and the loss (at an unknown period in time) of Hox4.[3] It is not known whether other taxa besides echinoids also possess this unusual Hox gene order.

## Research

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* Research Proposal

* Progress Record

## Academic Background

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### Overview

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This area of research involves learning about invertebrate zoology, neuroscience, and molecular lab techniques.

### Recommended Coursework

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* Comparative Neuroscience

### Other Materials

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* History of Life

* List of Animal Phyla

## Researchers

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* La comadreja formerly AFriedman RESEARCH (talk)

## References

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1. ↑ Arendt D. 2005. Genes and homology in nervous system evolution: Comparing gene functions, expression patterns and cell type molecular fingerprints. Theory in Biosciences 124:185-197.
2. ↑ Arendt D. 2008. The evolution of cell types in animals: emerging principles from molecular studies. Nature Reviews Genetics 9:868-882.
3. ↑ Mooi R, David B. 2008. Radial symmetry, the anterior/posterior axis, and echinoderm Hox genes. Annual Review of Ecology, Evolution and Systematics 39:43-62.