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Analysis of the genetic diversity of the nematode parasite Baylisascaris schroederi from 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 - Parasit Vectors (2013)

Bottom Line: For the DNA dataset, insignificant Fst values and a significant, high level of gene flow were detected among the three mountain populations of B. schroederi, and high genetic variation within populations and a low genetic distance were observed.Neutrality tests and mismatch analysis indicated that B. schroederi experienced a population expansion in the past.Taken together, the dispersed haplotype map, extremely high gene flow among the three populations of B. schroederi, low genetic structure and rapid evolutionary rate suggest that the B. schroederi populations did not follow a pattern of isolation by distance, indicating the existence of physical connections before these populations became geographically separated.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, China.

ABSTRACT

Background: Baylisascaris schroederi is 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 the B. schroederi population 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, 48 B. schroederi were 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 between B. schroederi and 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 of B. 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 that B. schroederi experienced a population expansion in the past.

Conclusions: Taken together, the dispersed haplotype map, extremely high gene flow among the three populations of B. schroederi, low genetic structure and rapid evolutionary rate suggest that the B. schroederi populations did not follow a pattern of isolation by distance, indicating the existence of physical connections before these populations became geographically separated.

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Map of the sampling sites. The geographical location of B. schroederi isolates collected from three different mountain ranges in China. The numbers of B. schroederi isolates (purple bars) and sampled hosts (green bars) from each mountain are shown respectively.
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Figure 1: Map of the sampling sites. The geographical location of B. schroederi isolates collected from three different mountain ranges in China. The numbers of B. schroederi isolates (purple bars) and sampled hosts (green bars) from each mountain are shown respectively.

Mentions: Adult B. schroederi (n = 48) were collected from 28 dead, injured or rescued giant pandas from three mountain ranges (Qinling, Minshan and Qionglai) during the period between May 2000 and May 2012 (details in Additional file1; Figure 1). Individual worms were washed in physiological saline, identified morphologically as B. schroederi[6], and stored at −20°C before DNA extraction. Total nematode genomic DNA was extracted from each specimen by standard proteinase K treatment and phenol/chloroform extraction[11], eluted into 30 μL TE buffer (pH 8.0) and stored at −20°C until analysis.


Analysis of the genetic diversity of the nematode parasite Baylisascaris schroederi from 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 - Parasit Vectors (2013)

Map of the sampling sites. The geographical location of B. schroederi isolates collected from three different mountain ranges in China. The numbers of B. schroederi isolates (purple bars) and sampled hosts (green bars) from each mountain are shown respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750503&req=5

Figure 1: Map of the sampling sites. The geographical location of B. schroederi isolates collected from three different mountain ranges in China. The numbers of B. schroederi isolates (purple bars) and sampled hosts (green bars) from each mountain are shown respectively.
Mentions: Adult B. schroederi (n = 48) were collected from 28 dead, injured or rescued giant pandas from three mountain ranges (Qinling, Minshan and Qionglai) during the period between May 2000 and May 2012 (details in Additional file1; Figure 1). Individual worms were washed in physiological saline, identified morphologically as B. schroederi[6], and stored at −20°C before DNA extraction. Total nematode genomic DNA was extracted from each specimen by standard proteinase K treatment and phenol/chloroform extraction[11], eluted into 30 μL TE buffer (pH 8.0) and stored at −20°C until analysis.

Bottom Line: For the DNA dataset, insignificant Fst values and a significant, high level of gene flow were detected among the three mountain populations of B. schroederi, and high genetic variation within populations and a low genetic distance were observed.Neutrality tests and mismatch analysis indicated that B. schroederi experienced a population expansion in the past.Taken together, the dispersed haplotype map, extremely high gene flow among the three populations of B. schroederi, low genetic structure and rapid evolutionary rate suggest that the B. schroederi populations did not follow a pattern of isolation by distance, indicating the existence of physical connections before these populations became geographically separated.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, China.

ABSTRACT

Background: Baylisascaris schroederi is 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 the B. schroederi population 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, 48 B. schroederi were 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 between B. schroederi and 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 of B. 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 that B. schroederi experienced a population expansion in the past.

Conclusions: Taken together, the dispersed haplotype map, extremely high gene flow among the three populations of B. schroederi, low genetic structure and rapid evolutionary rate suggest that the B. schroederi populations did not follow a pattern of isolation by distance, indicating the existence of physical connections before these populations became geographically separated.

Show MeSH
Related in: MedlinePlus