草原毒草白喉乌头的遗传多样性与遗传结构研究

通过测定采自天山和阿尔泰山草原的17个白喉乌头居群的叶绿体DNA片段序列,调查了其遗传多样性和空间遗传结构,并计算出每个居群的遗传多样性;运用分子变异方差(AMOVA)分析计算发生在居群内和居群间的遗传变异比例;利用错配分析来检验该物种是否发生了历史居群扩张;最后,基于最大熵方法模拟其物种在不同时期的分布区。结果表明:白喉乌头具有较低水平的遗传多样性(单倍型多样性±SD=0.343 7±0.048 8),所有居群均共享一个单倍型;遗传变异大致均等分布于居群间和局群内(58.25%vs.41.75%);两个不同谱系的分化发生在第四纪冰期(1.816~2.280百万年以前)末次盛冰期时期,该物种的避难所存在于天山西部,而在未来气候变化条件下其分布区不会发生变化。研究认为白喉乌头这种空间遗传结构与其克隆繁殖、长的生活周期、异交繁殖等生活史特征,以及第四纪气候变化影响相关。

Studies on genetic diversity and structure of a poisonous plant (Aconitum leucostomum)

Aconitum leucostomum is a widespread poisonous plant in grasslands of Xinjiang and causes a seri-ous risk to the local animal husbandry.This plant has high dispersal ability and high reproductive capacity.In this study,we investigated the spatial genetic pattern and the demographic history of 17 populations from Tians-han and Altai Mountains based on sequenced cpDNA region.The genetic diversity were computed for each popu-lation,the proportions of genetic variations occurred among populations or within populations were estimated based on analysis of molecular variance (AMOVA)method,The historical demographic expansions of this spe-cies was tested by pairwise mismatch distribution analysis.Finally,the potential distributions of this species were modeled using the maximum entropy approach based on different climatic periods.Results showed A.leu-costomum owned low level of genetic diversity (Hd = 0.343 7±0.048 8)and dominated by one haplotype in all populations.Genetic variation was almost equally distributed among populations and within populations (58.25% vs.41.75%).The characters of genetic structure were related with the life history traits of this poi-sonous species,such as clonal reproduction,long life cycle and outcrossing mode of reproduction.Molecular dat-ing indicated the Quaternary glacial periods triggered divergence between two phylogenetic lineages.Species dis-tribution modeling predicted this poisonous species owned LGM regugia at the western Tianshan Mounatins and will not change potential distributions during the future climatic scenarios (the 2050s and the 2070s).