根据cpDNA trnT-trnF序列变异分析中国互花米草种群的遗传结构

Analysis of the genetic structure of Spartina alterniflora populations in China based on cpDNA trnT-trnF sequences

采用直接测序法,测定了中国沿海互花米草8个种群80个样本的叶绿体trnT-trnF序列。结果显示,2个单碱基的插入/缺失将80个序列分为3种单倍型,3种单倍型在美国东海岸均有分布,且属于美国分布最广泛的C单倍型;中国种群的单倍型多样性Hd为0.379,远低于美国原产地;种群间基因分化系数Gst为0.103、固定指数Fst为0.092;AMOVA分析揭示种群间仅有9%的遗传差异。研究结果表明,中国互花米草种群受瓶颈效应影响明显,种群间遗传变异较低,种群内多样性相对较高。

Polymorphism of the chloroplast DNA（cpDNA） trnT-trnF sequence from eight Spartina alterniflora populations,including 80 samples in China,was measured.Three haplotypes,which were distinguished by two single A insertion/deletions（Indel）,were relatively lower haplotype diversity types（Hd=0.379） than the native populations,which indicated an obvious bottleneck effect.The mean values of Nei＇s genetic distance and genetic differentiation index（Fst） of eight populations were 0.064 and 0.092,and Nei＇s genetic distances ranged from 0.000 to 0.184.AMOVA revealed that there was 9% genetic variation in the total population.At the cpDNA level,there was a relatively lower level of genetic differentiation but S.alterniflora populations had a higher genetic differentiation within populations in China.