Phylogeographical Study on Eriophyton wallichii(Labiatae) from Alpine Scree of Qinghai-Tibetan Plateau

In this study,we examined the nuclear ribosomal DNA internal transcribed spacer(ITS) sequence variation of Eriophyton wallichii,a perennial endemic to scree of the Qinghai-Tibetan Plateau.Nineteen haplotypes were detected by analyzing 187 individuals from 20 populations of E.wallichii.Most populations hold the unique haplotype,which showed different population with different haplotype.An analysis of molecular variance(AMOVA) for populations showed that the genetic variation mainly resided among populations(89.54%),the level of differentiation among populations was very high(GST=0.863;NST=0.957) but didn' t show a significant phylogeographical structure.It is different from foregoing other species reported in Qinghai-Tibetan Plateau that the haplotypes of E.wallichii showed a distribution pattern that almost one population hold one unique haplotype,hardly share same halotype among populations.We hypothesized the unique genetic structure of E.wallichii might result from allopatric fragmentation in the islands of alpine due to the extremely isolated scree and rough topography of the region,through the Quaternary climate oscillation dramatically caused population expanding or shrinking.