| The immuno-competence of triploid salmon has been in contention for some time. Numerous studies have focused on performance without attention to the fundamental genetic difference between triploid and diploids. In this study, triploid and diploid Chinook salmon (Oncorhynchus tshawytscha) were used to examine the effects of polyploidy on specific and genome-wide gene expression response to a severe immune challenge using quantitative real time PCR (qRT-PCR) and microarray technology. Although triploid and diploid fish had significant differences in mortality, qRT-PCR revealed no differences in cytokine gene expression response (interleukin-8, interleukin-1, interleukin-8 receptor and tumor necrosis factor), while differences were observed in constitutively expressed genes, (IgM, MHC-II and β-actin). Genome-wide microarray analysis has revealed that, overall, triploid gene expression is similar to diploids as observed in their similar phenotypes. This balance, however, can be disrupted during stressful events such as immune challenges as shown at a select few assayed genes. |
