Phylogeography Of Iris Kobayashii Kitagawa

Dramatic changes in climate and environmental conditions during the Quaternary ice age have had profound and lasting effect on the current species distribution.The establishment and development of phylogeography have provided convenient and efficient methods for the research on phylogeny,glacial refuge.Phylogeography provides new means to uncover the mechanism of biodiversity,genetic structure of population,spatial distribution pattern of current species,and stimulated a new line of life science.Iris kobayashii Kitagawa,a perennial herb of genus Iris,Iridaceae,is endemic to China,which mainly distributing in the Songnen grassland,the south of Liaodong peninsula,Shandong peninsula and other regions.In order to understand the effect of Quaternary ice age fluctuation on the evolutionary history of I.kobayashii population,this study based on 10 chloroplast DNA(cpDNA)fragments and 11 nuclear microsatellite(nSSR)sites,and 6 groups,in total 65 I.kobayashii individuals were collected from the main distribution area,and carried out phylogeographic research,to uncover the phylogeographic patterns and the potential genetic diversity center of I.kobayashii.and as to explore the genetic diversity and population genetic structure of I.kobayashii,then reveal the origin of I.kobayashii in different distribution areas.Genetic diversity analysis based on cpDNA data and analysis based on nSSR data showed that,at the level of regions,the I.kobayashii populations distributing in Nanguanling,Dalian has the highest genetic diversity(NG:H_d=0.591,?=0.00086)and the largest number haplotype(H3,H4,H5),all of which is unique snp.The genetic diversity analysis based on nSSR showed the I.kobayashii population distributing in Nanguanling has the highest genetic diversity(NG:Na=76,Ne=1.1101,PPL=44.64%).The SNP geographical distribution map and network graph analysis based on cpDNA analysis showed that each main distribution area of I.kobayashii has the special SNPs,and the populations distributing in Shandong Peninsula(AQ,JN,LX)and Nanguanling are closely related phylogenetically.The affinity relationships between the populations from the Songnen Grassland(ZL)and Hulunbeier(SY)is apparently closer.SAMOVA analysis based on cpDNA data,as well as the STRUCTURE analysis of nSSR data and the results of NJ trees all showed that the populations(AQ?JN?LX)from Shandong Peninsula and the population from Nanguanling(NG)clustered into a group,as the populations(ZL)from Songnen Grassland and the populations from Hulunbeier(SY)clustered into another group.AMOVA analysis based on nSSR data showed that the genetic variation of I.kobayashii mainly originates within populations.The results show that each I.kobayashii population from different distribution areas has independent genetic diversity center respectively,and the genetic variations were positively correlated with the geographical distance,the geographical isolation caused the genetic differentiation among different populations of different distribution areas.This study shows,there were multiple refuge of I.kobayashii in the Quaternary ice age,which conforms to the northern refuge model,as while Nanguanling should be the most important refugia.This study provides reference and scientific evidence for the future studies on the speciation,phylogeny of genus Iris.