动物线粒体基因是系统发育、物种界定的最主要分子标记，其演化规律及驱动机制有助于筛选分子标记和解析系统发育分析结果。虽然其演化长期被认为是由突变驱动的中性演化，但近期对鸟类和蝙蝠等动物的研究显示：环境因素和飞行能力差异能驱动线粒体基因发生适应性演化。因此，我们推测同样具有飞行能力的昆虫，线粒体基因演化也受选择压力的影响，需要综合突变和自然选择压力两类因素研究其演化驱动机制。密码子作为系统演化数据兼有碱基的遗传信息和氨基酸的功能信息，其偏好性能定量反映出演化的程度。本项目以起源较早、种类丰富、类群分化多样的直翅目昆虫为研究对象，构建直翅目昆虫线粒体基因数据库；计算各物种和13个蛋白质编码基因的密码子参数，确定密码子的偏好性；对各种突变、选择压力参数与密码子偏好性进行相关性分析，发现线粒体基因演化的驱动机制。结果将为昆虫线粒体基因进化、系统发育分子标记选择和直翅目昆虫分类、进化等提供依据。

Mitochondrial genes are the most popular molecular markers for the animal phylogenetic study and species delimitation. The evolution trends and driving mechanism of animal mitochondrial DNA will help us on selecting the suitable molecular markers and explaining the phylogenetic results. For a long period, the evolution of mitochondrial genome has been regarded as neutral evolution driven by mutation solely. But, the studies on birds and bat mitogenome demonstrate that the environmental factors, the difference of flight ability also drive the adaptive evolution of mito-genome. Here, we hypothesize, the mitochondrial genome of the flighting insects is dominated by the selection pressure. We need to study the evolutionary driven mechanism of insect mitochondrial genes by combining the mutation and selective pressure. Codons have both the genetic information of DNA and functional information of amino-acid when used as phylogenetic code. The codon usage bias quantificationally reflects the evolution level of genes. The proposal will study the evolutionary and driven mechanism of mitochondrial genome of orthoptera insects. Firstly, an orthoptera mito-genomic database will be established. Then, the codon usage parameters of each species and 13 protein-coding genes will be calculated using bioinformatics methods to determine the codon bias; the correlation analysis of various mutations, selection evolutionary pressure and codon preference parameters will be analyzed to study the evolutionary drive mechanism of mitochondrial genes. This project will provide theoretical support for insect mitochondrial gene evolution, phylogenetic molecular marker selection, and the classification and evolution of orthoptera insects.