Parasitology

Research Article

Molecular characterization and phylogenetic analysis of ascarid nematodes from twenty-one species of captive wild mammals based on mitochondrial and nuclear sequences

YAN LIa1, LILI NIUa2, QIANG WANGa2, ZHIHE ZHANGa3, ZHIGANG CHENa1, XIAOBIN GUa1, YUE XIEa1, NING YANa1, SHUXIAN WANGa1, XUERONG PENGa4 and GUANGYOU YANGa1 c1

a1 Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an 625014, China

a2 Veterinary Hospital, Chengdu Zoological Garden, Chengdu, Sichuan 610081, China

a3 The Sichuan Key Laboratory for Conservation Biology on Endangered Wildlife – Developing toward a State Key Laboratory for China, Chengdu Research Base of Giant Panda Breeding, Chengdu, Sichuan 610081, China

a4 Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Ya'an 625014, China

SUMMARY

Although ascarid nematodes are important parasites of wild animals of public health concern, few species of ascarids from wild animals have been studied at the molecular level so far. Here, the classification and phylogenetic relationships of roundworms from 21 species of captive wild animals have been studied by sequencing and analysis of parts of the ribosomal 18S and 28S genes and the mitochondrial (mt) 12S gene. Phylogenetic relationships were inferred by 3 methods (NJ/MP/ML) based on the data of single gene sequences and concatenated sequences. Homology analysis indicated that the 18S sequences were conserved among roundworms from all 21 species and that 28S showed interspecies variability. Divergence levels displayed in 12S suggested that 12S appears to be either intra- or interspecifically variable. Evolutionary trees indicated that the ascarids split into 2 families, 4 genera and 7 species, with high bootstrap support for each clade. Combined trees suggested that Baylisascaris ailuri is more closely related to B. transfuga than to B. schroederi. This study provides useful molecular markers for the classification, phylogenetic analysis and epidemiological investigation of roundworms from wild animals.

(Received December 21 2011)

(Revised February 26 2012)

(Accepted March 05 2012)

(Online publication May 01 2012)

Correspondence:

c1 Corresponding author: Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an 625014, China. Tel: +86 835 2882787. Fax: +86 835 2885302. E-mail: guangyou1963@yahoo.com.cn

Footnotes

† These authors contributed equally to this work.

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