Diversity of the immunoglobulin heavy chain in the Atlantic salmon (Salmo salar L.) is contributed by genes from two parallel IgH isoloci.

Evolution of duplicated IgH loci in Atlantic salmon, Salmo salar

“…One interesting feature of the Atlantic salmon ( Salmo salar ) IgH locus is that it possesses two parallel IgH isoloci ( IGH-A and IGH-B ) [12,30-32], that are related to the tetraploid ancestry of the family Salmonidae [30,33]. A recent study by Shiina et al (2005) estimated the duplication event to have taken place approx.…”

Limited diversity of the immunoglobulin heavy chain variable domain of the emerald rockcod Trematomus bernacchii

“…E-mail: coscia@dafne.ibpe.na.cnr.it between genes of di#erent families [3]. An extensive analysis of VH genes in eight di#erent actinopterygian species has led to the following results: (1) Three distinct VH families have been identified in Carassius auratus (order Cypriniformes), where five sequences have been characterised [4]; (2) Three VH families have also been identified in Gadus morhua (order Gadiformes) [5], however, analysing a total of 115 unique clones, a fourth family has been added recently [6]; (3) Eight VH gene segments of Takifugu rubripes (order Tetradontiformes) have been grouped into two families [7]; (4) In Oncorhynchus mykiss (order Salmoniformes), where 46 VH sequences have been determined by di#erent authors, eleven VH families have been defined [8]; (5) By sequencing 13 VH cDNA clones, eight VH families, closely related to O. mykiss families, have been identified in the salmonid Salvelinus alpinus [9]; (6) Nine VH families have been found in another salmonid species, Salmo salar, of which seven were closely related to O. mykiss and S. alpinus VH families [10]; (7) Ictalurus punctatus (order Siluriformes) has been shown to have at least seven VH families, based on the characterisation of a total of 26 VH sequences [11,12,13]; (8) The VH sequences of 75 cDNA clones from Danio rerio (order Cypriniformes) fall into four families [14]; (9) Finally, 41 VH sequences from the chondrostean Acipenser baeri (order Acipenseriformes) have been classified in three distinct VH families [15]. These data indicate a widely di#erent number of families defined to date in di#erent species.…”

“…Furthermore, when the clustering relationship among VH genes belonging to the same family reveals further distribution, a number of subfamilies can be described. The rainbow trout VH I family has been subdivided into two subfamilies [16]; VH III of Atlantic cod in seven subfamilies, based on related amino acid motifs [6]; Atlantic salmon VH II and VH VI families each into two subfamilies [10]. It has been observed that family identity in a specific interval of the FR3 region can be also important to shape the antigen binding site [17].…”

“…Group D consists exclusively of bony fish VH genes and may be considered the major lineage for bony fish antibody evolution. Group E includes all VH genes from cartilaginous fish, a few amphibian genes, and the rainbow trout VH VIII, Arctic charr VH VIII, and Atlantic salmon VH VIII families [10].…”

“…Nucleotide identities between the Trbe IIa and VH IIb subfamilies ranged from 74-83%. In other species, the identities ranged: from 79-85% between the rainbow trout VH I subfamilies [16]; from 80-99% between the Atlantic cod VH III subfamilies [6]; from 74-99% between the Atlantic salmon VH IIa and VH IIb subfamilies, and from 66-99% between the two Atlantic salmon VH VI subfamilies [10].…”