Wu Jiasheng, Zeng Yanru, Huang Jianqing, Hou Wei, Zhu Jun, Wu Rongling
College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, PR China.
Genet Res. 2007 Feb;89(1):27-38. doi: 10.1017/S0016672307008622.
Whether there are different genes involved in response to different environmental signals and how these genes interact to determine the final expression of the trait are of fundamental importance in agricultural and biological research. We present a statistical framework for mapping environment-induced genes (or quantitative trait loci, QTLs) of major effects on the expression of a trait that respond to changing environments. This framework is constructed with a maximum-likelihood-based mixture model, in which the mean and covariance structure of environment-induced responses is modelled. The means for responses to continuous environmental states, referred to as reaction norms, are approximated for different QTL genotypes by mathematical equations that were derived from fundamental biological principles or based on statistical goodness-of-fit to observational data. The residual covariance between different environmental states was modelled by autoregressive processes. Such an approach to studying the genetic control of reaction norms can be expected to be advantageous over traditional mapping approaches in which no biological principles and statistical structures are considered. We demonstrate the analytical procedure and power of this approach by modelling the photosynthetic rate process as a function of temperature and light irradiance. Our approach allows for testing how a QTL affects the reaction norm of photosynthetic rate to a specific environment and whether there exist different QTLs to mediate photosynthetic responses to temperature and light irradiance, respectively.
是否存在参与响应不同环境信号的不同基因，以及这些基因如何相互作用以决定性状的最终表达，这在农业和生物学研究中具有至关重要的意义。我们提出了一个统计框架，用于定位对响应变化环境的性状表达有主要影响的环境诱导基因（或数量性状位点，QTL）。该框架由基于最大似然的混合模型构建，其中对环境诱导响应的均值和协方差结构进行建模。对于连续环境状态的响应均值，即反应规范，通过从基本生物学原理推导或基于对观测数据的统计拟合优度得出的数学方程，针对不同的QTL基因型进行近似。不同环境状态之间的残差协方差通过自回归过程进行建模。与不考虑生物学原理和统计结构的传统定位方法相比，这种研究反应规范遗传控制的方法有望具有优势。我们通过将光合速率过程建模为温度和光照强度的函数，展示了该方法的分析过程和能力。我们的方法允许测试一个QTL如何影响光合速率对特定环境的反应规范，以及是否分别存在不同的QTL来介导光合对温度和光照强度的响应。
