Qinling Region Cabbage Butterfly Genetic Diversity And Population Differentiation

Cabbage white butterfly(Pieris rapae) is widely distributed in China,whole the north temperate zone(from South America to Southern India).The feeding habits and adapt to environmental conditions result in many ecological and geographical populations,by long-time isolation and evolution,populations,cabbage butterfly populations gradually got a certain degree of genetic difference.Qinling Mountains is Palaearctic--Oriental boundary of China and world zoogeographical division.The analysis on P.rapae genetic diversity in Qinling Mountains can offer some theoretical basis for P.rapae genetic diversity and the zoogeographical division of China.The Random Amplified Polymorphic DNA(RAPD) technique is a method for examining the DNA polymorphism developed in 1990s.Based on PCR technology,it uses the single-stranded oligonucleotide of random sequence as primer to amplify the genomic DNA.The method is favored bacause it can examine a large amount of loci at the genome by use of many primers.It is advantageous for its haigh efficiency,quickness,small sample quantity and less requirements for sample quality,which resulted in its broad applications in the genetic fields of Botany,Zoology and other Subjects.In the study on genetic diverty of different P.rapae different geography populations,11 RAPD primers from 60 random primers,and 10 populations,60 individuals are used.The results show 77 clear and reproducible amplification bands,of which,64 bands are polymorphic ones.The total percentage of polymorphisms bands is 83.12%.Different primers have different RAPD loci and percentage of amplification bands among different populations.Based on the presence/absence of bands,Shannon's index shows that there are higher genetic diversity existing within P.rapae populations.Chang'an populatin has highest genetic diversity,the Shannon's index is 1.5399. Sanmenxia population has the lowest level,the Shannon's index is 0.8466.56.73%of the variation exists among populations.But little distinctness in morphology.Population differentiaton is the reason that is Geography distance,isolation and habitat,pesticide is likely to lead to pieris rapae Survival bottleneck.We did cluster analysis of all individual with genetic distance of pieris rapae by UPGMA.The result showed that:Liuba populations and Chang'an populations was close and shared a cluster,and Nanyang populations had close relative with the two above,Zhashui populations had close relative with the three above,Shangluo populations had close relative with the four above;pieris rapae Sanmenxia populations and Luoyang populations had close relaionship,and Ningqiang populations had close relationship with them;Pieris rapae Ankang populations and Yan'an populations had close relative.It might be related with the geographical distance,isolated area and ecological environment of Pieris rapae habitat.From the Nei's genetic identity and genetic distance,we could see that,the genetic identity and genetic distance of 10 Pieris rapae populations was 0.8945～0.7011 and 0.1182～0.3300.Pieris rapae Ankang populations and Yah'an populations' genetic identity is highest,Pieris rapae Ningqiang populations and Yan'an populations' genetic identity is lowest there were differences among different Pieris rapae populations.This result showed that the populations genetic differentiation coefficients 57.98%estimated by shannon information index was neutral.Cluster analysis on nine morphological charachers of male Pieris rapae in showed that,Pieris rapae Ningqiang populations and Liuba populations belonged to one geographical race;Pieris rapae Ankang populations and Shangluo populations belonged to one geographical race,which is morphologically similar with Chang'an populations and had close genetic variation with the two populations above;pieris rapae Luoyang populations and Sanmenxia populations belonged to one geographical race.It is in turn closed to Zhashui populations,Sanmenxia populatins and Nanyang populations on degree of Genetic variation.Numerical taxonomy and RAPD cluster accorded with the hindering effect of Qinling Mountains and the Loess Plateau to Pieris rapae.