Conserved pathways of limb development in vertebrate embryos

Type :

Term papers

Pages :

5 pages

Format :

.doc

Published date :

04/08/2009

Category :

Science & technology

Sub category :

Biology

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Summary :

Introduction
A study on developmental research
1. Specification of signaling systems
2. Localization of various signaling molecules
Formation and development of limbs within the vertebrate phylum
Overview of vertebrate limb development
Sonic Hedgehog on limb development
A study of conservative pathways
Conclusion
References

Abstract

Mice and chick embryos serve as ideal test subjects in the analysis of developmental characteristics. Through in-vivo manipulation, signaling frameworks have been constructed to explain and describe the development of limbs (Tickle, 2004). The basis of all development relies on several generalized processes. development begins with the separation of cell fields on the basis of function, as signaling pathways are introduced into each region. This causes a cascade of reactions, and ultimately the differentiation of cell types (Johnson and Tabin, 1997). The development of the limb itself is controlled by several interacting processes. Positional information and the identity of the limb features are regulated by the expression of sonic hedgehog, as well as a variety of BMP proteins. These factors function as concentration dependant morphogens, and result in variable responses based on the localized dosages (Tickle, 1999). The overall orientation of these appendages is regulate by a variety of transcriptional controls, and collectively maintained through hox gene expression (Tarchini and Duboule, 2006). Several similarities of these processes are conserved between vertebrate species, although the mechanisms responsible for signal interpretation result in the variability of morphologies observed (Tickle, 2004).