Aquaculture Europe 2021

October 4 - 7, 2021

Funchal, Madeira

Add To Calendar 06/10/2021 12:10:0006/10/2021 12:30:00Europe/LisbonAquaculture Europe 2021FUNCTIONAL GENOMIC ANALYSIS OF LANDLOCKED ATLANTIC SALMON Salmo salar POPULATIONSFunchal-HotelThe European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982

FUNCTIONAL GENOMIC ANALYSIS OF LANDLOCKED ATLANTIC SALMON Salmo salar POPULATIONS

 

Ross Cairnduff 1 *, Erik Kjærner-Semb1, Rolf B. Edvardsen1, Per Gunnar Fjelldal1, Tom Hansen1, Tom Ole Nilsen2 , Anna Wargelius1

 

 1  Institute of Marine Research, Bergen, Norway

 2 University of Bergen, Bergen, Norway

 E-mail: ross.fisher.cairnduff@hi.no

 



Introduction

 Given both the economic and societal impact of the Atlantic Salmon (Salmo salar) farming industry in Norway, increased knowledge around heritable traits, which may translate into welfare gains in both wild and farmed salmon, is of high demand. This may include  traits associated with  disease resistance, growth and sea-water adaption. G enetic potential may reside in  landlocked populations which have undergone different selection pressures  compared to  their anadromous counterparts for the last 10,000 year s,  due to their lack of sea water transfer, lack of marine pathogen pressures and different feed availability . We have in previous studies identified genes and genomic regions diverging between anadromous and landlocked Atlantic salmon populations from a widespread geographical distribution. H owever, we do not yet understand the biological significance of these diverged genomic regions,  spanning about  250  genes distributed on several chromosomes. Hence, the objective of this study was to increase the biological understanding of the genetic differences between anadromous and landlocked populations. From the 250 genes present in diverging regions, we picked 22 candidate genes previously associated with either disease resistance, growth and sea-water adaption in other species .  Gene expression was assayed in several tissues before and after  the predicted smoltification season  in a  common garden smoltification experiment including one-year old anadromous farmed salmon (Mowi) and landlocked salmon (Gullspång).

Results

 From the 22 genes we identified differential expression in 4 genes; ncor1 ,  encoding  a thyroid hormone mediator  in the gill was shown to be down- regulated in Gullspång post smoltification, while remaining fixed in the Mowi counterpart. spcs3 encodes a protein  involved in microsomal peptide signalling in the h ead kidney and was shown to be up- regulated in Mowi , while remaining fixed in Gullspång . csf2rb2 encodes an activator in the JAK-STAT pathway and was down- regulated in Gullspång  while  being fixed in Mowi . bcl2l13 , linked to adipocyte biogenesis, was significantly higher Gullspång than it was in Mowi .  To further investigate whether  the identified  genomic regions contain genetic variation relevant for understanding and improving traits in farmed salmon, we are currently  screening farmed salmon strains  for potential landlocked alleles  using  a genotype-by-sequencing (GT-seq) approach .  The plan is to perform  genotyping of 28 regions in the salmon genome in a vast material of farmed fish in which traits of interest have been quantified, such as growth and sea-water adaption.  This study provides a basis for further functional studies of candidate genes through the creation of knockout models and  subsequent functional studies including growth, disease and feeding trials.