扁穗冰草rDNA-ITS序列测定及分析

Sequence determination and analysis of the ITS region of nuclear ribosomal DNA in Agropyron cristatum(L.) Gaertn

提取青藏高原环湖地区扁穗冰草35个样品的DNA,采用PCR产物直接测序的方法,对扁穗冰草r DNA的ITS区(包括ITS-4和ITS-5)进行序列测定。结果表明:扁穗冰草ITS序列总长度为649bp,其中有17个变异位点,扁穗冰草物种水平的Hd、Pi分别为0.916和0.00320,表明扁穗冰草物种水平上的遗传多样性相对较高。AMOVA分析表明,扁穗冰草大部分的遗传变异发生在居群内(77.62%),在系统发育树中,虽然4个地区样品聚为3支,但是每一支中不同地区的个体混杂在一起。

DNAs of 35 samples of Agropyron cristatum （ L. ） Gaertn in the alpine region around Qinghai Lake area were extracted. The sequence of rDNA ITS region （ including ITS - 4 and ITS - 5 ） were determined by the direct of PCR products. The results showed that the full length of A. cristatum （ L. ） Gaertn ITS was about 649bp, The numbers of variable sites was 17 respectively. Haplotype diversity （Hd） and nucleotide diversity （Pi） at the species level were 0. 873 and 0.00407, respectively, ic diversity. Molecular variance analysis （AMOVA） which indicated that A. cristatum had a high level of genetindicated that high genetic differentiation （77.62%） exis ted within population. The phylogenetic tree based on NJ method suggested that although the populations were clustered into three groups, individuals from different region mixed together. This information provided an important molecular basis for the classification and determination of A. cristatum （L.）Gaertn zenus.