The evolutionary puzzle solution for the origins of the partial loss of the Cτ2 exon in notothenioid fishes.
Fish Shellfish Immunol
; 116: 124-139, 2021 Sep.
Article
em En
| MEDLINE
| ID: mdl-34038801
ABSTRACT
Cryonotothenioidea is the main group of fishes that thrive in the extremely cold Antarctic environment, thanks to the acquisition of peculiar morphological, physiological and molecular adaptations. We have previously disclosed that IgM, the main immunoglobulin isotype in teleosts, display typical cold-adapted features. Recently, we have analyzed the gene encoding the heavy chain constant region (CH) of the IgT isotype from the Antarctic teleost Trematomus bernacchii (family Nototheniidae), characterized by the near-complete deletion of the CH2 domain. Here, we aimed to track the loss of the CH2 domain along notothenioid phylogeny and to identify its ancestral origins. To this end, we obtained the IgT gene sequences from several species belonging to the Antarctic families Nototheniidae, Bathydraconidae and Artedidraconidae. All species display a CH2 remnant of variable size, encoded by a short Cτ2 exon, which retains functional splicing sites and therefore is included in the mature transcript. We also considered representative species from the three non-Antarctic families Eleginopsioidea (Eleginops maclovinus), Pseudaphritioidea (Pseudaphritis urvillii) and Bovichtidae (Bovichtus diacanthus and Cottoperca gobio). Even though only E. maclovinus, the sister taxa of Cryonotothenioidea, shared the partial loss of Cτ2, the other non-Antarctic notothenioid species displayed early molecular signatures of this event. These results shed light on the evolutionary path that underlies the origins of this remarkable gene structural modification.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Imunoglobulinas
/
Peixes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Fish Shellfish Immunol
Assunto da revista:
BIOLOGIA
/
MEDICINA VETERINARIA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Itália