Genome-scale comparative analysis for host resistance against sea lice between Atlantic salmon and rainbow trout

Action research is a systematic investigative research method that educators can use to improve aspects of their educational practice. Originally adopted in school situations, action research is becoming increasingly used within higher education. First, the paper explains the action research process. Second, the action research process is applied to a small-scale project undertaken by the authors in order to assist in the development of students’ research skills by encouraging them to read primary documents for themselves. Finally, the paper discusses the use and appropriateness of action research within accounting education. Some possible implications for accounting academe are also identified. It is argued that action research, with its emphasis on continuous improvement and the promotion of scholarly activity, is consistent with the accreditation standards issued by The Association to Advance Collegiate Schools of Business (AACSB)

Genetic parameters for Piscirickettsia salmonis resistance, sea lice (Caligus rogercresseyi) susceptibility and harvest weight in rainbow trout (Oncorhynchus mykiss)

Piscirickettsiosis caused by the intracellular bacterium Piscirickettsia salmonis and caligidosis produced by the ectoparasite Caligus rogercresseyi, are important diseases which generate great economic losses in salmonid farming in Chile. Selective breeding for pathogen resistance has been proposed as an alternative tool for the control of diseases. The objective of the present study is to determine the levels of genetic variation for resistance to P. salmonis and susceptibility to C. rogercresseyi, in addition to investigating the levels of genetic co-variation between these traits and harvest weight in rainbow trout. Resistance to P. salmonis was defined as individual day of death (SRS_DD) and as binary survival (SRS_BS) after an experimental challenge carried out by intraperitoneal injection of an inoculum based on LF89 strain. Susceptibility to C. rogercresseyi (CAL) was measured as the sum of the parasitic load on the pectoral and caudal fins per fish after an experimental challenge. Harvest weight (HW) was recorded in individuals genetically related to challenged fish and analyzed to determine the genetic correlations between this trait and the previous ones. A linear multi-trait animal model was used to estimate (co)variance components for SRS_DD, CAL and HW. A single-trait probit threshold animal model was used to estimate variance components for SRS_BS on the underlying scale. Bivariate linear animal models were used to estimate genetic correlations between SRS_BS on the observed scale and all other traits. The heritabilities for SRS_DD, CAL and HW were 0.45 ± 0.06, 0.08 ± 0.02 and 0.35 ± 0.06, respectively. The heritabilities for SRS_BS were 0.28 ± 0.03 and 0.38 ± 0.05 on the underlying and observed scale, respectively. The genetic correlation between SRS_DD and CAL and between SRS_BS and CAL were 0.39 ± 0.14 and −0.34 ± 0.15, respectively. All other genetic correlations assessed were not significant. We concluded that there is significant additive genetic variation for P. salmonis resistance and C. rogercresseyi susceptibility, which indicates that it is possible to genetically improve these traits in rainbow trout. In addition, there is an unfavorable genetic correlation between P. salmonis resistance and C. rogercresseyi susceptibility and a null genetic correlation between growth and these traits. These results suggest that resistance to P. salmonis or C. rogercresseyi can be simultaneously improved with harvest weight. However, simultaneous selection for P. salmonis and C. rogercresseyi resistance must account for the unfavorable genetic relationship between both traits in this rainbow trout breeding population

Genome wide association study for resistance to Caligus rogercresseyi in Atlantic salmon (Salmo salar L.) using a 50K SNP genotyping array

The sea louse (Caligus rogercresseyi) is an external parasite and considered one of the most important health problems in the salmon farming industry. Resistance to conventional chemical treatments has been demonstrated. Sufficient additive genetic variation has been determined to include selection for resistance to this parasite in Atlantic salmon breeding programs. The aim of this study was to perform a GenomeWide Association Study in order to dissect the genetic factors involved in the resistance to C. rogercresseyi, one of themost important species of sea lice in the Chilean salmon farming. 2628 Atlantic salmon smolts, which had been experimentally infested with C. rogercresseyi, were genotyped using a 50K SNP array. Genome Wide Association Analysis was conducted using a polygenic model. A heritability of 0.12 for resistance to this louse species was estimated using genomic information. This result was consistent with estimates from previous studies which used pedigree records in the same population. Only one SNP, located on chromosome 21, was significant at a local level, explaining 0.5% of the phenotypic variance and 4% of the genomic heritability for sea lice resistance. This SNP is located in an intronic region of a predicted gene which codes for Collagen alpha-1. Our results suggest that resistance to C. rogercresseyi can be considered a polygenic trait, controlled by many variants of relatively small effect. Thus the incorporation of genomic information through genomic selection could be the most appropriate approach for breeding purposes. Statement of relevance: Caligus resistance has a polygenic genetic architecture.National Commission of Scientific and Technologic Research (CONICYT) 21130669 21120382 Government of Canada CAPES, Government of Brazil Vicerrectoria de Investigacion y Desarrollo, Universidad de Chile project CORFO Innova-Chile 11IEI-12843 project UInicia Grant FONDEF NEWTON-PICARTE IT14I10100 CONICYT (Government of Chile) The British Council (Government of United Kingdom

Genomewide single nucleotide polymorphism discovery in Atlantic salmon (Salmo salar ) : validation in wild and farmed American and European populations

A considerable number of single nucleotide polymorphisms (SNPs) are required to elucidate genotype–phenotype associations and determine the molecular basis of important traits. In this work, we carried out de novo SNP discovery accounting for both genome duplication and genetic variation from American and European salmon populations. A total of 9 736 473 nonredundant SNPs were identified across a set of 20 fish by whole-genome sequencing. After applying six bioinformatic filtering steps, 200 K SNPs were selected to develop an Affymetrix Axiom® myDesign Custom Array. This array was used to genotype 480 fish representing wild and farmed salmon from Europe, North America and Chile. A total of 159 099 (79.6%) SNPs were validated as high quality based on clustering properties. A total of 151 509 validated SNPs showed a unique position in the genome. When comparing these SNPs against 238 572 markers currently available in two other Atlantic salmon arrays, only 4.6% of the SNP overlapped with the panel developed in this study. This novel high-density SNP panel will be very useful for the dissection of economically and ecologically relevant traits, enhancing breeding programmes through genomic selection as well as supporting genetic studies in both wild and farmed populations of Atlantic salmon using high-resolution genomewide information.Keywords : Genomic selection; Next-generation sequencing; Pseudo-tetraploid; Salmo salar; SNP arra