【作者】 马海霞；

【导师】 封烁；

【作者基本信息】 青海大学 ， 生态学， 2025， 硕士

【摘要】 全球气候快速变化对生物多样性造成巨大的威胁,种间适应性渐渗促进物种更好的适应环境变化,进一步提升森林生态系统物种多样性水平,因此理解林木物种适应性渐渗的遗传基础变得至关重要。本研究以云杉、青海云杉和白杄这三个云杉属近缘物种为研究对象,基于群体转录组数据,运用种群遗传学和景观基因组学方法,分析云杉、青海云杉和白杄的种群遗传结构,评估种群内核苷酸多态性水平及种群间遗传分化水平,检测三个近缘物种间基因流情况,鉴定物种分化过程中受选择的关键基因,探究种间适应性渐渗机制。主要研究结果如下:1.系统发育、主成分和种群遗传结构分析结果表明这三个物种之间已发生显著的遗传分化。种群内核苷酸多态性水平表明三个物种中云杉的核苷酸多样性水平最高（π=0.003532±0.003276）,青海云杉最低（π=0.003043±0.003044）。种群间而言,两两物种对之间均存在中等程度的分化。其中云杉和白杄的群体分化水平最高(F_ST=0.1290±0.1540),而云杉和青海云杉间最低(F_ST=0.0820±0.1090)。2.种间基因流检测结果表明三个物种间始终存在持续且不对等的基因流现象,经过分析,最终确定我们的模型是{[（云杉,青海云杉）,白杄]布鲁尔云杉},在该模型下分析得到D统计值为0.043,表明青海云杉和白杄之间存在的基因流明显大于云杉和白杄之间的基因流。基因渐渗结果表明,相比于云杉和白杄,在青海云杉和白杄之间存在更多的基因渐渗现象。3.通过挖掘与环境相关的适应性渐渗基因,鉴定到26个和抗逆性及开花时间等相关的基因。这些候选基因很可能促进了云杉、青海云杉和白杄对环境变化的适应性,揭示了适应性渐渗基因在促进物种适应性进化的作用机制。研究结果不仅加深了我们对云杉属物种间适应性渐渗机制的理解,还为应对环境变化背景下的物种保护和管理策略提供了重要的理论依据。更多还原

【Abstract】 Rapid global climate change poses a great threat to biodiversity,and interspecific adaptive infiltration promotes better adaptation of species to environmental changes and further enhances the level of species diversity in forest ecosystems,thus understanding the genetic basis of adaptive infiltration in forest species has become crucial.In this study,three closely related species of Picea asperata,P.crassifolia,and P.meyeri were taken as the research objects,based on population transcriptome data,population genetics and landscape genomics methods,the population genetic structure of P.asperata,P.crassifolia,and P.meyeri was analyzed,the level of nucleotide polymorphisms and the level of genetic differentiation between populations were evaluated,gene flow of the three closely related species were detected,the key genes selected in the process of species differentiation were identified,and the mechanism of interspecific adaptive introgression was explored.The main findings are as follows:1.The results of phylogenetic,principal component,and population genetic structure analysis showed that significant genetic differentiation had occurred between the three species.The nucleotide polymorphism level of the population showed that the nucleotide diversity level of P.asperata was the highest（π=0.003532±0.003276）among the three species and the lowest level of P.crassifolia（π=0.003043±0.003044）.Regarding,there is a moderate degree of differentiation between two pairs.The population differentiation level of P.asperata and P.meyeri was the highest(F_ST=0.1290±0.1540),while the lowest level was among P.asperata and P.crassifolia(F_ST=0.0820±0.1090).2.The results of the interspecific gene flow test indicated that there was always a continuous and unequal gene flow phenomenon among the three species,and after analysis,we finally determined that our model was{[（P.asperata,P.crassifolia）,P.meyeri]P.breweriana},and the D-statistic value obtained from the analysis under this model was 0.043,which indicated that there was a gene flow between P.crassifolia and P.meyeri that was significantly larger than that between P.asperata and P.meyeri.The results of gene introgression showed that there were more gene introgressions between P.crassifolia and P.meyeri compared with P.asperata and P.meyeri.3.By mining the adaptive introgression genes related to the environment,26 of key genes such as stress resistance and flowering time were discovered.These candidate genes may have promoted the adaptability of P.asperata,P.crassifolia,and P.meyeri to environmental changes,revealing the mechanism of adaptive introgression genes in promoting adaptive evolution.The results of this study not only deepen our understanding of the mechanism of adaptive introgression between Picea species but also provide an important theoretical basis for species conservation and management strategies in the context of environmental change.更多还原