泛性寄生虫能感染多种宿主且地理分布广泛，是多种动物疫病的元凶。对其与宿主相互关系的研究是了解种间协同演化历史，以及疾病发生和传播的基础，鸟类血孢子虫便是此类研究理想的模式系统。在自然选择作用下，泛性鸟类血孢子虫可能由于对不同宿主的适应性演化，或因地理隔离导致基因流受阻而正在分化或已然分化为不同的物种。目前基于形态学特征的分类可能导致物种界定的偏差，很大程度上限制了对宿主-寄生虫协同演化的准确理解。近年来随着鸟类血孢子虫基因组靶向序列捕捉和测序方法的建立，基于分子证据对其进行物种厘定成为可能。.本研究以在我国能感染多种野生鸟类，且对宿主危害较大的残疟原虫(Plasmodium relictum)为研究对象，1）应用基因组水平的多基因序列，厘清不同宿主的地理种群是否为多个隐存种，2）构建血孢子虫和宿主的协同演化关系，分析宿主系统发育、地理分布和生态位分化对寄生虫物种分化的影响。

Presumed generalist parasites are mostly widespread and are responsible for multiple emerging infectious diseases. Understanding the associations between generalist parasites and their hosts is of fundamental importance to basic research of disease evolution, and avian haemosporidian parasites are ideal model systems for studying host-parasite associations. Because of local adaptations to different host species, a generalist haemosporidian parasite may readily evolve into several specialists unless there is sufficient gene flow between parasites infecting different species of hosts. However we are still in lack of robust methods to accurately define cryptic species in most parasites..In this project, we focus on Plasmodium relictum, a generalist parasite which caused great harm to its avian hosts, aiming at obtaining genome-wide sequences from multiple host species in different geographical regions and settling the following issues: 1) define whether P. relictum in different hosts represent the same species or multiple cryptic species, 2) investigate the co-evolutionary pattern between P. relictum and its avian host species, and how did geographical distributions and ecological niches of hosts shape parasite speciation.