Department of Biological Sciences and Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada.
Heredity (Edinb). 2010 Feb;104(2):224-34. doi: 10.1038/hdy.2009.108. Epub 2009 Aug 26.
Understanding how organisms function at the level of gene expression is becoming increasingly important for both ecological and evolutionary studies. It is evident that the diversity and complexity of organisms are not dependent solely on their number of genes, but also the variability in gene expression and gene interactions. Furthermore, slight differences in transcription control can fundamentally affect the fitness of the organism in a variable environment or during development. 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 using quantitative real-time PCR (qRT-PCR) and microarray technology after an immune challenge with the pathogen Vibrio anguillarum. 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), whereas differences were observed in constitutively expressed genes, (immunoglobulin (Ig) M, major histocompatibility complex (MHC) -II and beta-actin) upon live Vibrio anguillarum exposure. Genome-wide microarray analysis revealed that, overall, triploid gene expression is similar to diploids, consistent with their similar phenotypes. This pattern, however, can subtly be altered under stress (for example, handling, V. anguillarum challenge) as we have observed at some housekeeping genes. Our results are the first report of dosage effect on gene transcription in a vertebrate, and they support the observation that diploid and triploid salmon are generally phenotypically indistinguishable, except under stress, when triploids show reduced performance.
了解生物体在基因表达水平上的功能对于生态和进化研究变得越来越重要。显然，生物体的多样性和复杂性不仅取决于其基因数量，还取决于基因表达和基因相互作用的可变性。此外，转录控制的微小差异可能从根本上影响生物体在可变环境或发育过程中的适应性。在这项研究中，使用三倍体和二倍体奇努克鲑鱼（Oncorhynchus tshawytscha）来研究多倍体对特定和全基因组基因表达反应的影响，使用定量实时 PCR（qRT-PCR）和微阵列技术，在受到病原体鳗弧菌免疫挑战后。尽管三倍体和二倍体鱼的死亡率存在显著差异，但 qRT-PCR 显示细胞因子基因表达反应（白细胞介素-8、白细胞介素-1、白细胞介素-8 受体和肿瘤坏死因子）没有差异，而在暴露于活鳗弧菌时，组成型表达基因（免疫球蛋白（Ig）M、主要组织相容性复合体（MHC）-II 和β-肌动蛋白）存在差异。全基因组微阵列分析表明，总体而言，三倍体基因表达与二倍体相似，与其相似的表型一致。然而，这种模式在应激下（例如，处理、鳗弧菌挑战）可能会微妙地改变，正如我们在一些管家基因中观察到的那样。我们的研究结果首次报道了脊椎动物中基因转录的剂量效应，并且支持这样的观察结果，即除了在应激下，三倍体表现出性能下降外，二倍体和三倍体鲑鱼通常表型上无法区分。
