[Genetic variations in four geographical isolates of based on cytochrome b and internal transcribed spacer genes].

OBJECTIVE

To investigate the genetic diversity and genetic differentiation of different geographical isolates of

METHODS

isolates were sampled from Wuhu (WH), Bengbu (BB) and Bozhou cities (BZ) of Anhui Province and Jiaxing City of Zhejiang Province (JX). Mitochondrial cytochrome b (Cytb) and ribosomal internal transcribed spacer (ITS) genes were amplified in WH, BB, BZ and JX isolates of using PCR assay. The gene sequences were edited and aligned using the software Chromas 2 and DNASTAR 1.00, and the haplotype, haplotype diversity (Hd) and nucleotide polymorphism (Pi) of each isolate were calculated using the software DnaSP 5.10.00. The genetic differentiation among isolates () and gene flow value () were estimated using the software MEGA 10.2, and a phylogenetic tree was built. Tests of neutrality and analysis of molecular variance (AMOVA) were performed using the software Arlequin 3.1 and a haplotype network was built based on the Median-Joining network using the software Network 10.2.

RESULTS

PCR assay showed that the sizes of the and genes were 372 bp and 1 301 to 1 320 bp, respectively. All four isolates of presented high genetic diversity based on mitochondrial and genes (Hd = 0.804, Pi = 0.006 91). AMOVA showed genetic differentiation among geographical isolates of ( = 0.202 40, < 0.05), and the genetic variation was mainly caused by intra-population variations (79.76%). Gene flow analysis showed a high level of gene flow among isolates ( > 1). Tests of neutrality based on gene measured a Tajima's value of -1.796 31 ( < 0.05) and a Fu's value of -3.293 98 ( < 0.05) in WH isolate of , indicating population expansion in WH isolate of Haplotype network analysis and phylogenetic analysis revealed no remarkable geographical distribution pattern among different geographical isolates of All four isolates of presented high genetic diversity (Hd = 0.985, Pi = 0.011 97). AMOVA showed moderate level of genetic differentiation between four isolates ( = 0.104 62, < 0.05). The tests of neutrality based on genes measured a Tajima's value of -6.088 20 and a Fu's value of -1.935 99 (both > 0.05) in the whole isolate of , indicating no obviously population expansion.

CONCLUSIONS

The four geographical isolates of have high genetic diversity and remarkable genetic differentiation. Since a high level of gene flow is detected among different geographical isolates of , no obvious geographical distribution pattern of is found.