Understanding how gene expression is translated to phenotype is central to modern molecular biology, and the success is contingent on the intrinsic tractability of the specific traits under examination. However, an a priori estimate of trait tractability from the perspective of gene expression is unavailable. Motivated by the concept of entropy in a thermodynamic system, we here propose such an estimate (S_T) by gauging the number (N) of expression states that underlie the same trait abnormality, with large S_T corresponding to large N. By analyzing over 200 yeast morphological traits, we show that S_T predicts the tractability of an expression-trait relationship. We further show that S_T is ultimately determined by natural selection, which builds co-regulated gene modules to minimize possible expression states.

了解基因表达如何转化为表型是现代分子生物学的核心，而成功的前提是所检查的特定性状具有内在的易处理性。但是，无法从基因表达的角度对性状易处理性进行先验估计。通过在热力学系统熵的概念的启发，我们在这里提出这样的估计（小号_Ť通过测量数（）ñ背后同一性状异常，具有大的表达状态的）小号_Ť对应于大Ñ。通过分析200多种酵母的形态特征，我们发现S _T预测表达特征关系的易处理性。我们进一步表明，S _T最终是由自然选择决定的，它建立了共同调节的基因模块，以最大程度地减少可能的表达状态。