转座子是细胞生物基因组的主要组成部分，其在细胞生物中具有非常重要的作用。然而由于绝大多数病毒的基因组在大小上有严格的限制且基因密度非常高，任何插入都可能对病毒产生有害影响，因此病毒会通过反选择消除它。这种天生固有的属性使得病毒基因组中转座子是非常罕见的。因此，转座子在病毒中的作用仍然是个谜，亟待研究。2018年申请人意外发现超级巨型病毒潘多拉中的转座子非常丰富，该发现暗示我们有望突破瓶颈，从而重新认识转座子在病毒中的作用。本项目拟以潘多拉病毒为模型，通过大量的生物信息学分析研究转座子在潘多拉病毒中的进化模式和对其新基因形成的贡献，并鉴定出转座子介导的基因组重组现象；同时，通过多种环境压力的诱导实验，研究转座子在潘多拉病毒适应不同环境压力中的作用。研究结果对于理解病毒中新基因的起源及物种的形成有重要意义，并为理解病毒适应宿主及其环境压力提供新线索，进而为病毒病的防控和治疗提供一个新视角。

Transposable elements (TEs) represent major components of cellular organisms, and they play important roles in their genomes. However, most viruses have a genome strictly limited in size and have high gene density. In such compact genomes, any insertion is likely to have a deleterious effect for the virus, which would result in its elimination by counter selection. TEs are exceptionally rare in viruses as a result of the above innate characterization. Therefore, functions of TEs in the viral genomes remain a mystery and is an urgent need to study. In 2018, the applicant unexpectedly found that TEs in pandoraviruses were very abundant. This finding suggests that we may break through the bottleneck and re-recognize the role of TEs in viruses. This project will take pandoraviruses virus as a model to study the evolution pattern of TEs in pandoraviruses, their contribution to the formation of new genes , and identify the phenomena of transposon-mediated genome recombination through a large number of bioinformatics analysis. Meanwhile, the roles of TEs in the adaptation of pandoraviruses to different environmental pressures was studied by induction experiments of various environmental pressures. The results are of great significance for understanding the origin of new genes and the formation of species in viruses, and provide new clues for understanding the adaptation of viruses to host and their environmental pressures, thus providing a new perspective for the prevention, control and treatment of viral diseases.