Studies On Phylogeography And Speciation Of Pinus Henryi Mast. And Pinus Tabuliformis Carr. Based On DNA Sequencing Technology

Pinus henryi Mast., mainly distributes over Wushan Mountains,Daba Mountains and offshoots of YunGui Plateau.But the numbers are limited,this species is listed as a rare plant.The primary task of protecting endangered species is to determine the distribution of species,clarify the relationship between species and relatives.However,there are problems in these two areas for Pinus henryi Mast.:Pinus henryi is ofen regarded as the taxonomic variant species of Pinus massoniana or Pinus tabuliformis.Some experts argued that it should be independent species.According to the geographic distribution, Pinus henryi is linked with Pinus tabuliformis,and overlaps with Pinus massoniana.For a long time there are many disputes on P. henryi and P.tabuliformis view of the geographical boundaries.This study is from the perspective of molecular systematics,making use of DNA molecular sequencing technology,we analyzed molecular phylogeography and species formation, for P.henryi,P.tabuliformis and Pmassoniana,two mitochondrial fragments (Nad4,Nad5) and chloroplast fragments (TrnS-TrnG,Rpl16) were screened.According to sequence variation of 27 populations of 225 individuals for genetic diversity and genetic differentiation analysis,We identify the geographical distribution of haplotype patterns and phylogenetic relationships;trace the evolution of the modern distribution of population history,the geographical boundaries of locations,historical reasons of distribution pattern and possible glacial refuges.The results show that:(1)Two mitochondrial DNA sequence variations were identified 11 haplotypes. All populations can be divided into three groups according to spatial distribution of mtDNA haplotypes:(â… )Bashan-Wuling Mountain;(â…¡)Qinling Southern Slope;(â…¢)Qinling Northern Slope.Population genetic characteristics are as follows:space analysis of molecular variance of 27 populations were divided into three groups to maximize the group differentiation(FCT=0.78);Nucleotide diversity (Ï€)on species level is 0.00377;haplotype diversity(h)is 0.745.The AMOVA analysis reveals:genetic variation mainly exists among groups,genetic differentiation among populations(FST)is 0.52;the genetic diversity is not high(HS=0.228),and the total genetic diversity(HT=0.568-0.000) among the populations varies significantly;The population differentiation index (GST=0.762,NST=0.853) is high and the gene flow(Nm=0.38)is lower, phylogeographical structure(NST>GST,0.010.1);However, a major haplotype exists in the most populations,resulting in genetic differentiation among the populations is small; Although we don't find the same style of population differentiation and the phylogeographical structure of chloroplast DNA as the mitochondrial DNA,it provides a basis for the origin and evolution.(3) Tajima's D (Tajima 1989),Fu and Li's D*,Fu and Li's F* (Fu & Li 1993) test show that populations don't reject neutral evolution hypothesis.(4)The result of this study shows that:P.henryi and P.tabuliformis, P. massoniana can't be classified as the same group,in this study it isn't appropriate as a variant of P.tabuliformis or P. massoniana,we should regard it as a separate species.it's origin is the hybrid product of two lineages(P.tabuliformis,P.massoniana);geographical boundary for P.henryi and P.tabuliformis is Qinling-Daba Mountains.(5)mtDNA distribution and phylogenetic analysis of haplotype,the Nest Clade Analysis show that:the refuges are in the Qinling,Micang Mountains,Daba Mountains and Wuling Mountains;In post-glacial age populations did't experience significant population expansion process.