动物食性分化是自然选择的结果，也是导致动物消化酶基因发生适应性进化的重要动力。雀小目鸟类（Passerida）食性多样性丰富，系统发育框架较清晰，是追溯动物食性分化起源与演化的理想研究对象。本研究拟对40多个雀小目代表物种的11类消化酶基因分别进行序列测定和分子进化分析， 再结合对已公开基因组数据的分析， 揭示不同食性鸟类消化酶基因的序列变异和进化模式，鉴定出假基因、完整基因和复制基因，估算消化酶假基因的形成时间，阐释完整基因的分布特点，鉴定复制基因的选择压力；同时，检测可能有功能变化的消化酶基因在特定组织的表达水平，测定重组消化酶蛋白的酶活性差异，探讨鸟类消化酶的表达差异和功能改变。本项目拟从消化酶基因的分子进化与消化酶活性差异的角度，研究雀小目鸟类主要代表类群的食性转变的进化历史，揭示食性差异在雀小目鸟类适应辐射中的作用和分子机制。

Dietary diversification in animals, which resulted from natural selection, is an important drive force of adaptive evolution of digestive enzyme genes. The avian clade Passerida has evolved the great diversity in diets, within a relatively established phylogenetic framework, and thus members of Passerida are excellent study subjects to trace the origin and evolution of dietary diversification. In this work, we will sequence 11 classes of digestive enzyme genes in over 40 representative species from Passerida, and undertake evolutionary analysis in combination with publicly available genome data. We aim to characterize the sequence variations and evolutionary patterns of digestive enzyme genes in birds with different diets, date the formation of pseudogenes, describe the distribution of intact genes, and identify selective forces of duplicated genes. Furthermore, we will evaluate expression differences of digestive enzymes with possible functional changes in some digestive tissues, and examine changes of digestive enzyme activities, with the aim of studying changes in expression and functions of digestive enzymes. By examining molecular evolution of digestive enzyme genes and changes of digestive enzyme activities, this work will explore the evolutionary history of dietary transition in representative species of Passerida, and attempt to reveal molecular basis of dietary diversification and its roles in adaptive radiation of Passerida.