Analysis of genetic differentiation among different geographic populations of Aphis glycines (Hemiptera: Aphididae) based on mtDNA COⅡ gene sequences
Author of the article:LI Ran** HAN Lan-Lan** WANG Hong ZHAO Kui-Jun*** MANG Yi-Lun ZHANG Hong-Yu FAN Dong
Author's Workplace：College of Agriculture, Northeast Agricultural University, Harbin 150030, China
Key Words：Aphis glycines, mtDNA COⅡ, geographic population, genetic differentiation, gene flow (Nm)
Abstract： [Objectives] To investigate genetic variation among different geographic populations of soybean aphids, Aphis glycines, in China. [Methods] The genetic diversity, genetic differentiation, and molecular variance of 339 individual soybean aphids from 14 geographic populations in 7 Chinese provinces were analyzed based on 673 bp segments of the mitochondrial cytochrome c oxidase subunit Ⅱ (COⅡ) gene using DnaSP 5.0, Arlequin 3.5.1.2 and Network 4.6.1.3. Phylogenetic trees and the networks of COⅡ haplotypes were constructed from the resultant data. [Results] A total of 7 haplotypes were identified; haplotype No.1 (H1) was shared by all 14 populations. A low level of genetic diversity (Hd=0.479±0.030, Pi=0.00166±0.00018) in the total population was detected and higher genetic differentiation (Fst=0.1985) and a high level of gene flow (Nm=2.019) was apparent among different geographic populations. The results of a Neutral test (Tajima's D=﹣0.931, P>0.10, Fu’s Fs=0.220, P>0.10) were not significant, indicating that there is no evidence of recent population expansion. The analysis of molecular variance (AMOVA) showed no obvious genetic differentiation among populations with a high proportion of the total genetic variance attributable to variation within populations (80.15%). A phylogenetic tree and a haplotype network based on haplotypes of the different geographic populations shows no obvious geographical structure in different clades. [Conclusion] Genetic diversity of different geographical populations of soybean aphids is low, and there is no significant linear correlation between geographic distance and genetic differentiation; gene flow between different geographic populations is not affected by geographic distance.