ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2016, Vol. 47 ›› Issue (4): 796-804.doi: 10.11843/j.issn.0366-6964.2016.04.020

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Genetic Variation of Heterakis gallinarum in Sichuan based on the Nuclear Ribosomal DNA Internal Transcribed Spacer Regions (ITS1/2)

GU Xiao-bin1#* ,ZHU Jun-yang1# ,WANG Bao-jian1,ZHENG Jing2,YANG Guang-you1,WANG Tao1,LAI Wei-min1   

  1.  (1.College of Veterinary Medicine,Sichuan Agricultural University,Chengdu 611133,China;2.Sichuan Entry-exit Inspection and Quarantine Bureau,Chengdu 610041,China)
  • Received:2015-10-20 Online:2016-04-23 Published:2016-04-23

Abstract:

The aim of the present study was to analyze the characteristic of genetic variability in Heterakis gallinarum populations from Sichuan province,and provide a foundation for understanding the epidemiology and assist in the control of heterakiasis.The nuclear ribosomal DNA internal transcribed spacer region (ITS1-5.8S-ITS2) of 59 H.gallinarum isolates from chickens belonged to 7 different geographical regions were amplified using the polymerase chain reaction (PCR) and then sequenced.Sequences unit containing ITS1 and ITS2 (excepting 5.8S) were used to determine the genetic variability and genetic structure of H.gallinarum in Sichuan province,China.Meanwhile,the relationships of this nematode with selected members of genus Heterakis were assessed by phylogenetic analysis of ITS1/2 sequence datasets by maximum parsimony (MP) and maximum likelihood (ML).Results showed that 59 H.gallinarum ITS1/2 sequences identity ranged from 98.9% to 100.0%,and ITS1 sequences displayed greater variability than ITS2.Fifty-nine sequences contained 20 variable sites,and were classified into 14 haplotypes (H1-H14).The overall Sichuan population showed high haplotype diversity (Hd = 0.532) and low nucleotide diversity (π=0.000 94).Meanwhile,a frequency of gene flow (Nm=31.72),a low degree of genetic differentiation (Fst=0.007 82),and an overwhelming genetic variability (99.22%) were observed within the overall Sichuan population.Phylogenetic trees (MP and ML) and haplotype network were both revealed that 7 different geographical regions did not form significant geographical populations.The different species within genus Heterakis were well distinguished in phylogenetic trees (MP and ML).Our results indicate that there is a high gene flow and low degree of genetic diversity across H.gallinarum population.

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