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@article{565930,
author = {Ottová, Eva and Šimková, Andrea and Martin, JeanandFrancois and Gouy de Bellocq, Joelle and Gelnar, Milan and Allienne, JeanandFrancois and Morand, Serge},
article_number = {3},
keywords = {Cyprinid species; MHC evolution; DAB genes; Diversifying and purifying selection; Molecular adaptation},
language = {eng},
issn = {1050-4648},
journal = {Fish and Shellfish Immunology},
title = {Evolution and trans-species polymorphism of MHC class IIB genes in cyprinid fish},
volume = {18},
year = {2005}
}
TY - JOUR
ID - 565930
AU - Ottová, Eva - Šimková, Andrea - Martin, Jean-Francois - Gouy de Bellocq, Joelle - Gelnar, Milan - Allienne, Jean-Francois - Morand, Serge
PY - 2005
TI - Evolution and trans-species polymorphism of MHC class IIB genes in cyprinid fish
JF - Fish and Shellfish Immunology
VL - 18
IS - 3
SP - 199-222
EP - 199-222
PB - Elsevier
SN - 10504648
KW - Cyprinid species
KW - MHC evolution
KW - DAB genes
KW - Diversifying and purifying selection
KW - Molecular adaptation
N2 - The polymorphism of DAB genes encoding MHC IIb was investigated in 11 cyprinid species from central Europe.The species belonged to four subfamilies: Cyprininae, Tincinae, Gobioninae and Leuciscinae. Two paralogous groups of sequences, DAB1 and DAB3, were recognised according to the similarity of their nucleotide and amino-acid sequences and from phylogenetic analyses using either partial exon 2 or partial exon 3 sequences. A high allelic variability among species was found for exon 2, indicating extensive MHC polymorphism. Time divergence estimation supports the separation of DAB1 and DAB3 groups predating the separation into fish subfamilies, and a cyprinid origin of the DAB genes. Phylogenetic trees using exon 2 support the hypothesis of trans-species polymorphism, which appears to be limited to the subfamily level, i.e. the presence of sequences from different species in the same allelic group was more often recognised within subfamilies Cyprininae and Leuciscinae than between them. Phylogenetic trees using exon 3 reflect the phylogenetic patterns previously found for Cyprinidae systematics. Specific nucleotides and amino-acids in exon 3 that separate both subfamilies, as well as the species within the Cyprininae subfamily were observed. A lack of segregation in leuciscin species was recognised and the alleles of different leuciscin species tend to share similar motifs in exon 3. This could be explained by the ancient and complicated dispersion history of Cyprininae and the radiation of Leuciscinae. The effects of selective pressures were investigated: (1) within species, (2) among lineages, and(3) among sites. From intraspecific analyses, exon 2 sequences were identified as the targets of diversifying selection, whilst the evolution of exon 3 seems to be under the influence of purifying selection. The analyses among lineages indicate positive selection in many branches when using exon 2, therefore confirming trans-species polymorphism, whilst the DAB lineages of exon 3 are potentially submitted to purifying selection to some extent. Moreover, our results suggest the secondary acquisition of function of DAB1 group after duplication. The analyses among sites reveal that exon 2 exhibits sites under positive selection mostly corresponding to the putative PBR sites involved in the a-helix structure of the protein.
ER -
OTTOVÁ, Eva, Andrea ŠIMKOVÁ, Jean-Francois MARTIN, Joelle GOUY DE BELLOCQ, Milan GELNAR, Jean-Francois ALLIENNE a Serge MORAND. Evolution and trans-species polymorphism of MHC class IIB genes in cyprinid fish. \textit{Fish and Shellfish Immunology}. Elsevier, 2005, roč.~18, č.~3, s.~199-222. ISSN~1050-4648.
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