Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules

<p>Abstract</p> <p>Background</p> <p>In the accompanying paper by Virginie Rouillon and myself, our demonstration that homogenisation by gene conversion occurs readily among MHC class I genes was made possible because of the exceptional conservation of the CD94L locus b...

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Main Author: Joly Etienne
Format: Article
Language:English
Published: BMC 2006-01-01
Series:Biology Direct
Online Access:http://www.biology-direct.com/content/1/1/3
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author Joly Etienne
author_facet Joly Etienne
author_sort Joly Etienne
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>In the accompanying paper by Virginie Rouillon and myself, our demonstration that homogenisation by gene conversion occurs readily among MHC class I genes was made possible because of the exceptional conservation of the CD94L locus between divergent species of separate taxa, suggesting that the molecules of this family are endowed with very important and well preserved biological functions. These results lead me to elaborate various hypotheses on several aspects of MHC evolution.</p> <p>Hypotheses</p> <p>In a first part, I propose a highly hypothetical scenario of MHC evolution that could explain how modern day CD94L molecules can have so many diverse and well preserved biological functions. Next, I propose that MHC class I molecules evolve more rapidly and exuberantly than class II molecules because the former are subjected to more direct selective pressures, in particular from viruses. Third, I suggest that concerted evolution, by increasing inter-genic homogeneity would in turn favour further inter-allelic and inter-loci exchanges, hence resulting in a more evolvable MHC. As a fourth and last point, I propose that the high GC content of sequences coding for classical class I molecules could be a consequence of biased gene conversion.</p> <p><b>Testing of these various hypotheses </b>should occur naturally over the coming years, with the ever increasing availability of more sequences related to MHC class I genes from various organisms. Ultimately, a better understanding of how MHC molecules evolve may help to decipher where and how our adaptive immune system arose, and keeps evolving in the face of the permanent challenge of infectious organisms.</p> <p>Reviewers</p> <p>This article was reviewed by Stephan Beck, Lutz Walter and Pierre Pontarotti.</p>
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spelling doaj.art-d26920b74c0143f89f213055b91160d82022-12-22T03:07:20ZengBMCBiology Direct1745-61502006-01-0111310.1186/1745-6150-1-3Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia moleculesJoly Etienne<p>Abstract</p> <p>Background</p> <p>In the accompanying paper by Virginie Rouillon and myself, our demonstration that homogenisation by gene conversion occurs readily among MHC class I genes was made possible because of the exceptional conservation of the CD94L locus between divergent species of separate taxa, suggesting that the molecules of this family are endowed with very important and well preserved biological functions. These results lead me to elaborate various hypotheses on several aspects of MHC evolution.</p> <p>Hypotheses</p> <p>In a first part, I propose a highly hypothetical scenario of MHC evolution that could explain how modern day CD94L molecules can have so many diverse and well preserved biological functions. Next, I propose that MHC class I molecules evolve more rapidly and exuberantly than class II molecules because the former are subjected to more direct selective pressures, in particular from viruses. Third, I suggest that concerted evolution, by increasing inter-genic homogeneity would in turn favour further inter-allelic and inter-loci exchanges, hence resulting in a more evolvable MHC. As a fourth and last point, I propose that the high GC content of sequences coding for classical class I molecules could be a consequence of biased gene conversion.</p> <p><b>Testing of these various hypotheses </b>should occur naturally over the coming years, with the ever increasing availability of more sequences related to MHC class I genes from various organisms. Ultimately, a better understanding of how MHC molecules evolve may help to decipher where and how our adaptive immune system arose, and keeps evolving in the face of the permanent challenge of infectious organisms.</p> <p>Reviewers</p> <p>This article was reviewed by Stephan Beck, Lutz Walter and Pierre Pontarotti.</p>http://www.biology-direct.com/content/1/1/3
spellingShingle Joly Etienne
Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
Biology Direct
title Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
title_full Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
title_fullStr Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
title_full_unstemmed Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
title_short Various hypotheses on MHC evolution suggested by the concerted evolution of CD94L and MHC class Ia molecules
title_sort various hypotheses on mhc evolution suggested by the concerted evolution of cd94l and mhc class ia molecules
url http://www.biology-direct.com/content/1/1/3
work_keys_str_mv AT jolyetienne varioushypothesesonmhcevolutionsuggestedbytheconcertedevolutionofcd94landmhcclassiamolecules