Evolution of major histocompatibility complex class I and class II genes in the brown bear
Abstract Background Major histocompatibility complex (MHC) proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB...
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ftbiomed:oai:biomedcentral.com:1471-2148-12-197 2023-05-15T18:42:16+02:00 Evolution of major histocompatibility complex class I and class II genes in the brown bear Kuduk, Katarzyna Babik, Wiesław Bojarska, Katarzyna Śliwińska, Ewa B Kindberg, Jonas Taberlet, Pierre Swenson, Jon E Radwan, Jacek 2012-10-02 http://www.biomedcentral.com/1471-2148/12/197 en eng BioMed Central Ltd. http://www.biomedcentral.com/1471-2148/12/197 Copyright 2012 Kuduk et al.; licensee BioMed Central Ltd. Positive selection Antigen binding sites MHC gene expression Phylogenetic analysis Orthology Ursidae Research article 2012 ftbiomed 2012-12-02T00:58:04Z Abstract Background Major histocompatibility complex (MHC) proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB genes in the brown bear Ursus arctos to characterise the level of polymorphism, estimate the strength of positive selection acting on them, and assess the extent of gene orthology and trans-species polymorphism in Ursidae . Results We found 37 MHC class I, 16 MHC class II DRB, four DQB and two DQA alleles. We confirmed the expression of several loci: three MHC class I, two DRB, two DQB and one DQA. MHC class I also contained two clusters of non-expressed sequences. MHC class I and DRB allele frequencies differed between northern and southern populations of the Scandinavian brown bear. The rate of nonsynonymous substitutions (d N ) exceeded the rate of synonymous substitutions (d S ) at putative antigen binding sites of DRB and DQB loci and, marginally significantly, at MHC class I loci. Models of codon evolution supported positive selection at DRB and MHC class I loci. Both MHC class I and MHC class II sequences showed orthology to gene clusters found in the giant panda Ailuropoda melanoleuca . Conclusions Historical positive selection has acted on MHC class I, class II DRB and DQB, but not on the DQA locus. The signal of historical positive selection on the DRB locus was particularly strong, which may be a general feature of caniforms. The presence of MHC class I pseudogenes may indicate faster gene turnover in this class through the birth-and-death process. South–north population structure at MHC loci probably reflects origin of the populations from separate glacial refugia. Article in Journal/Newspaper Ursus arctos BioMed Central |
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Open Polar |
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BioMed Central |
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ftbiomed |
language |
English |
topic |
Positive selection Antigen binding sites MHC gene expression Phylogenetic analysis Orthology Ursidae |
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Positive selection Antigen binding sites MHC gene expression Phylogenetic analysis Orthology Ursidae Kuduk, Katarzyna Babik, Wiesław Bojarska, Katarzyna Śliwińska, Ewa B Kindberg, Jonas Taberlet, Pierre Swenson, Jon E Radwan, Jacek Evolution of major histocompatibility complex class I and class II genes in the brown bear |
topic_facet |
Positive selection Antigen binding sites MHC gene expression Phylogenetic analysis Orthology Ursidae |
description |
Abstract Background Major histocompatibility complex (MHC) proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB genes in the brown bear Ursus arctos to characterise the level of polymorphism, estimate the strength of positive selection acting on them, and assess the extent of gene orthology and trans-species polymorphism in Ursidae . Results We found 37 MHC class I, 16 MHC class II DRB, four DQB and two DQA alleles. We confirmed the expression of several loci: three MHC class I, two DRB, two DQB and one DQA. MHC class I also contained two clusters of non-expressed sequences. MHC class I and DRB allele frequencies differed between northern and southern populations of the Scandinavian brown bear. The rate of nonsynonymous substitutions (d N ) exceeded the rate of synonymous substitutions (d S ) at putative antigen binding sites of DRB and DQB loci and, marginally significantly, at MHC class I loci. Models of codon evolution supported positive selection at DRB and MHC class I loci. Both MHC class I and MHC class II sequences showed orthology to gene clusters found in the giant panda Ailuropoda melanoleuca . Conclusions Historical positive selection has acted on MHC class I, class II DRB and DQB, but not on the DQA locus. The signal of historical positive selection on the DRB locus was particularly strong, which may be a general feature of caniforms. The presence of MHC class I pseudogenes may indicate faster gene turnover in this class through the birth-and-death process. South–north population structure at MHC loci probably reflects origin of the populations from separate glacial refugia. |
format |
Article in Journal/Newspaper |
author |
Kuduk, Katarzyna Babik, Wiesław Bojarska, Katarzyna Śliwińska, Ewa B Kindberg, Jonas Taberlet, Pierre Swenson, Jon E Radwan, Jacek |
author_facet |
Kuduk, Katarzyna Babik, Wiesław Bojarska, Katarzyna Śliwińska, Ewa B Kindberg, Jonas Taberlet, Pierre Swenson, Jon E Radwan, Jacek |
author_sort |
Kuduk, Katarzyna |
title |
Evolution of major histocompatibility complex class I and class II genes in the brown bear |
title_short |
Evolution of major histocompatibility complex class I and class II genes in the brown bear |
title_full |
Evolution of major histocompatibility complex class I and class II genes in the brown bear |
title_fullStr |
Evolution of major histocompatibility complex class I and class II genes in the brown bear |
title_full_unstemmed |
Evolution of major histocompatibility complex class I and class II genes in the brown bear |
title_sort |
evolution of major histocompatibility complex class i and class ii genes in the brown bear |
publisher |
BioMed Central Ltd. |
publishDate |
2012 |
url |
http://www.biomedcentral.com/1471-2148/12/197 |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_relation |
http://www.biomedcentral.com/1471-2148/12/197 |
op_rights |
Copyright 2012 Kuduk et al.; licensee BioMed Central Ltd. |
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1766231895483351040 |