Characterization of 40 full-length MHC class IIA functional alleles in miiuy croaker: Polymorphism and positive selection.
Dev Comp Immunol
; 55: 138-43, 2016 Feb.
Article
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| MEDLINE
| ID: mdl-26598111
ABSTRACT
The major histocompatibility complex is a highly polymorphic gene superfamily in vertebrates that plays an important role in adaptive immune response. In the present study, we identified 40 full-length miiuy croaker MHC class IIA (Mimi-DAA) functional alleles from 26 miiuy croaker individuals and found that the alleles encode 30 amino acid sequences. A high level of polymorphism in Mimi-DAA was detected in miiuy croaker. The rate of non-synonymous substitutions (d(N)) occurred at a significantly higher frequency than that of synonymous substitutions (d(S)) in the peptide-binding region (PBR) and non-PBR. This result suggests that balancing selection maintains polymorphisms at the Mimi-DAA locus. Phylogenetic analysis based on the full-length sequences showed that the Mimi-DAA alleles clustered into three groups. However, the phylogenetic tree constructed using the exon 2 sequences indicated that the Mimi-DAA alleles clustered into two groups. A total of 22 positively selected sites were identified on the Mimi-DAA alleles after testing for positive selection, and five sites were predicted to be associated with the binding of peptide antigen, suggesting that a few selected residues may play a significant role in immune function.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Perciformes
/
Antígenos de Histocompatibilidad Clase II
/
Proteínas de Peces
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Dev Comp Immunol
Año:
2016
Tipo del documento:
Article