基于简化基因组测序GBS黄翅大白蚁种群进化研究

Macrotermes barneyi (Light), is distributed in the central and southern areas of China and Vietnam. They distributed across the Palaearctic and Oriental regions, is the tropical subterranean fungus-growing termite distributed the world's most north limit. It colonized successfully to Hubei, Anhui and Jiangsu Province northwardly in Yangtze River basin region, northernmost to Henan, and eastward to Fujian, but it has not distributed incomprehensibly in Taiwan Province where more warmly. Although its biology and ecology aspects are well studied, their evolutionary origins remain poorly understood. Most termite forage below ground or above ground within shelter tubes due to low tolerance to desiccation, but M. barneyi forage in open air above the ground at suitable moisture levels. As a topical tropical termite, M. barneyi is capable of adaptation to a relatively low temperature, it even keep its tropical ancestral mound-building habit in late autumn. As a representatives of the termite genus Macrotermes, M. barneyi display a wide variety of nesting habits and ecological adaptation success, making it an ideal species for investigating the evolution of sympatric speciation, cold resistance, termites hidden life and mound building. Because they feed on a variety of substrates, it also provides an opportunity to illuminate the evolution of termite diets. Termite adaptation to low temperature, genomic analyses reveal demographic history and temperate adaptation of M. barneyi. The genetic evolutionary relationships of different geographical populations of M. barneyi were studied by a greater number of usable selected SNPs by Genotyping-by-Sequencing (GBS) approach, find the main factor affecting genetic structure and gene flow in populations of M. barneyi, to provide speciation evidence of the sympatric higher Macrotermes termite species and evolutionary physiology of insect thermal adaptation to cold environments.

黄翅大白蚁Macroterme barneyi分布越南和我国华南、华中，横跨东洋区和古北区，为世界分布最北的热带培菌地下白蚁。黄翅大白蚁向北成功拓展到湖北、安徽和江苏等沿长江流域，最北至河南，东至福建，但在隔海相望、气候更温暖的台湾省却无分布。人们对黄翅大白蚁生物学、生态学有一定研究，但对其起源进化还缺乏了解。多数白蚁需在蚁路或者掩蔽物下活动，但黄翅大白蚁在某些情况下可以进行裸露采食。它属于典型热带培菌白蚁，却能抵御冬季低温，甚至还保留有热带大白蚁祖先构筑地面土垄巢的痕迹。黄翅大白蚁是研究白蚁同域物种分化、抗寒性、食物多样化、白蚁隐蔽生活和筑巢等习性遗传进化不可多得的材料。本研究拟通过简化基因组测序技术对不同地理种群黄翅大白蚁单寡核苷酸多态性的筛选，研究其种群进化，探索影响黄翅大白蚁种群遗传结构和基因流的主要因子，为同域高等大白蚁属物种成功生态适应和白蚁对低温环境的进化生理学提供实验证据。

黄翅大白蚁Macrotermes barneyi (Light, 1924)，等翅亚目、白蚁总科Termitoidae、白蚁科Termitidae、大白蚁亚科Macrotermitinae、大白蚁属Macrotermes的一个重要种类，是我国南方堤坝、园林和森林的重要害虫。我国分布于江西，安徽，江苏，浙江，福建，台湾，湖南，湖北，广东，广西，海南，四川，贵州，云南，香港等省区，分布越南和我国华南、华中，横跨东洋区和古北区，为世界分布最北的热带培菌地下白蚁，是分布最北限的热带白蚁之一。黄翅大白蚁COI基因序列A+T含量(59.5%)高于C+G含量((40.5%), COII基因A+T含量(64.6%)明显高于C+G含量(3 5 .4%)，且COII基因突变区域大于COI。黄翅大白蚁COI/COII基因不同地理种群的遗传距离在0.002~0.005和0.002~0.024之间。通过对我国不同地理种群的黄翅大白蚁进行SNP分子标记检测和遗传多样性分析，研究了其不同地理种群的遗传进化关系。结果表明：1、不同省市地区的黄翅大白蚁存在着一定的遗传变异，同一省市不同地区的黄翅大白蚁也存在着一定的遗传变异。2、线粒体遗传差异的结果是由于地理隔离，不同地理种群在不同的生态环境下不断适应和进化而产生的，其存在复杂多变的遗传变异。3、广东、广西和海南区域为黄翅大白蚁种群的发育中心，从该中心区域向东部内陆，逐渐形成了福建、江西、湖南和浙江内陆支系，向西部边陲形成了广西、云南和贵州西南支系。4、黄翅大白蚁各地理种群只是相对独立，但相互之间又呈现镶嵌、套叠关系，尚没有比较清晰的分离关系，如果地理阻隔明显，则相对分离清晰，如果没有地理阻隔，则上述镶嵌、套叠关系明显。