Novel class II alpha MHC variability in a small peripheral Atlantic salmon population

2017 ◽  
Vol 48 (3) ◽  
pp. 370-372
Author(s):  
Kate L. Ciborowski ◽  
William C. Jordan ◽  
Carlos García de Leániz ◽  
Sofia Consuegra
2007 ◽  
Vol 274 (1611) ◽  
pp. 861-869 ◽  
Author(s):  
Elvira de Eyto ◽  
Philip McGinnity ◽  
Sofia Consuegra ◽  
Jamie Coughlan ◽  
Jarle Tufto ◽  
...  

Pathogen-driven balancing selection is thought to maintain polymorphism in major histocompatibility (MH) genes. However, there have been few empirical demonstrations of selection acting on MH loci in natural populations. To determine whether natural selection on MH genes has fitness consequences for wild Atlantic salmon in natural conditions, we compared observed genotype frequencies of Atlantic salmon ( Salmo salar ) surviving in a river six months after their introduction as eggs with frequencies expected from parental crosses. We found significant differences between expected and observed genotype frequencies at the MH class II alpha locus, but not at a MH class I-linked microsatellite or at seven non-MH-linked microsatellite loci. We therefore conclude that selection at the MH class II alpha locus was a result of disease-mediated natural selection, rather than any demographic event. We also show that survival was associated with additive allelic effects at the MH class II alpha locus. Our results have implications for both the conservation of wild salmon stocks and the management of disease in hatchery fish. We conclude that natural or hatchery populations have the best chance of dealing with episodic and variable disease challenges if MH genetic variation is preserved both within and among populations.


2017 ◽  
Vol 33 (7) ◽  
pp. 1004-1015 ◽  
Author(s):  
G. A. Maynard ◽  
M. T. Kinnison ◽  
J. D. Zydlewski

1993 ◽  
Vol 177 (6) ◽  
pp. 1699-1712 ◽  
Author(s):  
E K Bikoff ◽  
L Y Huang ◽  
V Episkopou ◽  
J van Meerwijk ◽  
R N Germain ◽  
...  

We used gene targeting techniques to produce mice lacking the invariant chain associated with major histocompatibility complex (MHC) class II molecules. Cells from these mice show a dramatic reduction in surface class II, resulting from both defective association of class II alpha and beta chains and markedly decreased post-Golgi transport. The few class II alpha/beta heterodimers reaching the cell surface behave as if empty or occupied by an easily displaced peptide, and display a distinct structure. Mutant spleen cells are defective in their ability to present intact protein antigens, but stimulate enhanced responses in the presence of peptides. These mutant mice have greatly reduced numbers of thymic and peripheral CD4+ T cells. Overall, this striking phenotype establishes that the invariant chain plays a critical role in regulating MHC class II expression and function in the intact animal.


<i>Abstract</i>.—Atlantic salmon <i>Salmo salar </i>smolts are stocked in the Penobscot River, Maine to supplement declining populations. Since 2000, approximately 550,000 hatchery smolts are annually released into the river, of which 32% of these (175,000) were marked with visual implant elastomer (VIE) tags indicating release time and location. Our study found that tag colors of adult returns were often misread due to confusion between green and yellow marks and between red and pink marks. Using data collected on mark readings in a controlled hatchery environment, we corrected for tag identification errors made in the field, thereby allowing adjustments to be made in the marked returns to accurately assess the number of returns from multiple stocking groups. When adult returns from multiple stocking groups were compared, significant differences were detected between stocking groups, including a three-fold difference between two of the stocking groups. Hence, a simple change in smolt stocking locations and times may be of value in the recovery of the Penobscot River salmon population.


2020 ◽  
Vol 77 (2) ◽  
pp. 593-603 ◽  
Author(s):  
Ana Almodóvar ◽  
Graciela G Nicola ◽  
Daniel Ayllón ◽  
Clive N Trueman ◽  
Ian Davidson ◽  
...  

Abstract Historical data on the oceanic distribution and migration routes of southernmost Atlantic salmon Salmo salar populations from Europe are almost non-existent, as no rigorous tagging initiatives have been conducted. Here, we used stable isotope data (δ13C and δ15N) of historic scale collections to identify the potential marine feeding areas of the largest salmon population in the Iberian Peninsula. Data were compared with published datasets from Northern Ireland, Wales, south England, and northeast UK coast, which correspond to series between 15- and 33-year long within the time period from 1958 to 2009. Temporal covariation in sea surface temperature, primary productivity, and δ13C values suggests that feeding areas of Iberian salmon are located around Greenland, both in the Labrador and the Irminger seas. Furthermore, δ13C values of Atlantic salmon from Canadian rivers reported in the literature are similar to those found in individuals from Spanish rivers. Our results suggest that Iberian salmon follow a westerly migration route towards Greenland instead of following the easterly branch of the North Atlantic current into the Norwegian Sea. Characterization of feeding patterns and migration routes might help to understand the causes of ongoing population decline and establish targeted conservation programmes for threatened Iberian salmon.


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