Atlantic salmon populations reveal adaptive divergence of immune related genes - a duplicated genome under selection

BMC Genomics

Research Article

Carl J. Rubin¹  Geir Dahle²  Vidar Wennevik²  Anna Wargelius²  Fernando Ayllon²  Rolf B. Edvardsen²  Tomasz Furmanek²  Erik Kjærner-Semb³  Kevin A. Glover³  Mikhail Ozerov⁴  Juha-Pekka Vähä⁵  Eero Niemelä⁶ 

[1] Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden;Institute of Marine Research, Bergen, Norway;Institute of Marine Research, Bergen, Norway;Department of Biology, University of Bergen, Bergen, Norway;Kevo Subarctic Research Institute, University of Turku, Turku, Finland;Kevo Subarctic Research Institute, University of Turku, Turku, Finland;Association for Water and Environment of Western Uusimaa, Uusimaa, Finland;Natural Resources Institute Finland, Helsinki, Finland;

关键词: Whole genome duplication;    Adaptation;    Aquaculture;    Immune system;    GWAS;    Resequencing;    Selective sweep;    SNPs;    Salmo salar;   

DOI  :  10.1186/s12864-016-2867-z

 received in 2016-02-27, accepted in 2016-06-30,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundPopulations of Atlantic salmon display highly significant genetic differences with unresolved molecular basis. These differences may result from separate postglacial colonization patterns, diversifying natural selection and adaptation, or a combination. Adaptation could be influenced or even facilitated by the recent whole genome duplication in the salmonid lineage which resulted in a partly tetraploid species with duplicated genes and regions.ResultsIn order to elucidate the genes and genomic regions underlying the genetic differences, we conducted a genome wide association study using whole genome resequencing data from eight populations from Northern and Southern Norway. From a total of ~4.5 million sequencing-derived SNPs, more than 10 % showed significant differentiation between populations from these two regions and ten selective sweeps on chromosomes 5, 10, 11, 13–15, 21, 24 and 25 were identified. These comprised 59 genes, of which 15 had one or more differentiated missense mutation. Our analysis showed that most sweeps have paralogous regions in the partially tetraploid genome, each lacking the high number of significant SNPs found in the sweeps. The most significant sweep was found on Chr 25 and carried several missense mutations in the antiviral mx genes, suggesting that these populations have experienced differing viral pressures. Interestingly the second most significant sweep, found on Chr 5, contains two genes involved in the NF-KB pathway (nkap and nkrf), which is also a known pathogen target that controls a large number of processes in animals.ConclusionOur results show that natural selection acting on immune related genes has contributed to genetic divergence between salmon populations in Norway. The differences between populations may have been facilitated by the plasticity of the salmon genome. The observed signatures of selection in duplicated genomic regions suggest that the recently duplicated genome has provided raw material for evolutionary adaptation.

【 授权许可】

CC BY   
© The Author(s). 2016