Analysis of the genetic diversity of the nematode parasiteBaylisascaris schroederifrom wild giant pandas in different mountain ranges in China
Zhou X, Xie Y, Zhang ZH, Wang CD, Sun Y, Gu XB, Wang SX, Peng XR, Yang GY.
Abstract
BACKGROUND:Baylisascaris schroederiis one of the most common nematodes of the giant panda, and can cause severe baylisascarosis in both wild and captive giant pandas. Previous studies of the giant pandas indicated that this population is genetically distinct, implying the presence of a new subspecies. Based on the co-evolution between the parasite and the host, the aim of this study was to investigate the genetic differentiation in theB. schroederipopulation collected from giant pandas inhabiting different mountain ranges, and further to identify whether the evolution of this parasite correlates with the evolution of giant pandas.
METHODS:In this study, 48B. schroederiwere collected from 28 wild giant pandas inhabiting the Qinling, Minshan and Qionglai mountain ranges in China. The complete sequence of the mitochondrial cytochrome b (mtCytb) gene was amplified by PCR, and the corresponding population genetic diversity of the three mountain populations was determined. In addition, we discussed the evolutionary relationship betweenB. schroederiand its host giant panda.
RESULTS:For the DNA dataset, insignificant Fst values and a significant, high level of gene flow were detected among the three mountain populations ofB. schroederi,and high genetic variation within populations and a low genetic distance were observed. Both phylogenetic analyses and network mapping of the 16 haplotypes revealed a dispersed pattern and an absence of branches strictly corresponding to the three mountain range sampling sites. Neutrality tests and mismatch analysis indicated thatB. schroederiexperienced a population expansion in the past.
CONCLUSIONS:Taken together, the dispersed haplotype map, extremely high gene flow among the three populations ofB. schroederi, low genetic structure and rapid evolutionary rate suggest that theB.schroederipopulations did not follow a pattern of isolation by distance, indicating the existence of physical connections before these populations became geographically separated.
Copyright ©2013 Zhou et al.; licensee BioMed Central Ltd.
Parasit Vectors. 2013 Aug 8;6:233. doi: 10.1186/1756-3305-6-233.Read full text:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3750503/
