Chapter

Evolutionary Conservation of NCL Proteins

P.E.M. Taschner

in The Neuronal Ceroid Lipofuscinoses (Batten Disease)

Second edition

Published on behalf of Oxford University Press

Published in print March 2011 | ISBN: 9780199590018
Published online November 2012 | e-ISBN: 9780191753459 | DOI: http://dx.doi.org/10.1093/med/9780199590018.003.0019

Series: Contemporary Neurology Series

Evolutionary Conservation of NCL Proteins

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Sequence analysis of DNA from different organisms has revealed that genes and their encoded proteins show more or less similarity depending on the distance between organisms in the tree of life. This similarity is the molecular evidence of the evolution of species from a common ancestor. During evolution, DNA damaging agents and errors during DNA replication have introduced changes, resulting in the variations found between species and also between individuals. In general, DNA variations between the protein-encoding regions of genes show least variation compared to intergenic or intronic sequences. The requirement to maintain the function of essential genes and proteins restrains the number of variations and is considered to be the basis of the evolutionary conservation of proteins. Many aspects of protein evolution have been reviewed recently (Pal et al., 2006). In the context of NCL research, the most important applications of evolutionary protein conservation are: 1) the identification of conserved residues and motifs in genes and proteins, which are considered to be functionally important and can cause disease, when altered, and 2) the identification of homologous genes and proteins in model organisms. Homologous genes and proteins can either be orthologues, which have directly evolved from a common ancestor and are functionally equivalent, or paralogues, which are the result of gene duplications within a species. After gene duplication, the paralogues may have evolved separately to obtain different functionalities.

Chapter.  1304 words.  Illustrated.

Subjects: Neurology

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