Diploid hybrid origin of Hippophaë gyantsensis (Elaeagnaceae) in the western Qinghai–Tibet Plateau

摘要: Homoploid hybrid speciation, the origin of a species without change in chromosome number, is currently considered to be rare form speciation. In present study, we examined phylogenetic Hippophae gyantsensis, diploid occurring western Qinghai-Tibet Plateau. Some its morphological and molecular traits suggest close relationship H.rhamnoides ssp. yunnanensis while others indicate H.neurocarpa. We conducted analyses sequence data two maternally inherited chloroplast (cp) DNA fragments bi-parentally nuclear ribosomal internal transcribed spacer (ITS) from 17 populations H.gyantsensis, 15 27 H.neurocarpa across their distributional ranges, modelled niche differentiation three taxa. Multiple lines evidence suggested that H.gyantsensis morphologically stable, genetically independent ecologically distinct species. The inconsistent placements clade comprised dominant cpDNA haplotypes ITS ribotypes probable multiple crosses between This tentative hypothesis more parsimonious than alternative explanations according available, although based on further testing needed.