利用叶绿体微卫星标记分析东亚柳杉群体的谱系地理结构

Phylogeographic Structure of Cryptomeria japonica in East Asia Using Chloroplast Microsatellite Markers

柳杉(Cryptomeria japonica)是东亚特有孑遗植物,分为中国柳杉(C.japonica var.sinensis)和日本柳杉(C.japonica var.japonica)两个地理变种,但其谱系空间格局与形成机制仍不清楚。本研究利用叶绿体微卫星(cpSSR)标记,研究东亚柳杉群体的遗传多样性及其谱系地理结构,分析空间分布与现有谱系之间的关联。结果表明,11个cpSSR多态性位点共检测到127个单倍型,各群体的单倍型数(A)从4到16不等,不同群体私有单倍型数(P)为1~11个。在物种水平,柳杉遗传多样性高(H=0.890),且遗传分化显著(FST=0.594,P<0.001)。与其空间分布一致,基于cpSSR标记的STRUCTURE分析将柳杉分为中国柳杉和日本柳杉两大群体,群体间存在明显谱系地理结构(G_(ST)=0.102<R_(ST)=0.702)。结合气候变化资料,推测第四纪气候变化和长期地理隔离是东亚柳杉谱系地理格局形成的主要原因。研究结果可为东亚植物区系演化和柳杉遗传资源保护提供科学依据。

Cryptomeria japonica is an endemic relic plant in East Asia,which has two recognized varieties of C.jqponica var.sinensis and C.japonica var.japonica.The lineage spatial pattern and the formation mechanism of this species are still unclear.In this study,we used chloroplast microsatellite(cpSSR)markers to explore the genetic diversity and phylogeographic structure of C.japonica populations and to analyze the relationship between spatial distribution and phylogenetic evolution.The results showed that a total of 127 haplotypes was detected based on 11 polymorphic cpSSR loci,and the number of haplotypes(A)ranged from 4 to 16,among which the number of private haplotypes(P)ranged from 1 to 11 in each population.In the species level,C.japonica has high genetic diversity(H=0.890)and significant genetic differentiation(Fsr=0.594,P<0.001).Consistent with its spatial distribution,all populations can be divided into two groups of C.japonica var.sinensis and C.japonica var.japonica based on cpSSR data.There was an obvious phylogeographic structure that existed among populations(G_(sr)=0.102<R_(sr)=0.702)in East Asia.Combined with the climate change data,it is speculated that the Quaternary climate change and long-term geographical isolation were the main factors for the phylogeographic distribution pat-tern of different lineages in East Asia.The results can provide scientific basis for the flora evolution of East Asia and the conservation of genetic resources of C.japonica.