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Origin and expansion of the Yunnan Shoot Borer, Tomicus yunnanensis (coleoptera: scolytinae): a mixture of historical natural expansion and contemporary human-mediated relocation.

Lü J, Hu SJ, Ma XY, Chen JM, Li QQ, Ye H - PLoS ONE (2014)

Bottom Line: Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago.Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one.Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, 650091, China.

ABSTRACT
The Yunnan shoot borer, Tomicus yunnanensis, is a recently-discovered, aggressive pest of the Yunnan pine stands in southwestern China. Despite many bionomics studies and massive controlling efforts, research on its population genetics is extremely limited. The present study, aimed at investigating the origin and dispersal of this important forestry pest, analyzed the population genetic structure and demographic history using a mitochondrial cox1 gene fragment. Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago. Host separation and specialization might have caused the speciation of T. yunnanensis. Genetic structure analyses identified two population groups, with six populations near the origin area forming one group and the remaining six populations from western and eastern Yunnan and southwestern Sichuan comprising the other. Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one. Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan. Our findings implied that T. yunnanensis underwent both historical expansion and recent dispersal. The historical expansion may relate to the oscillation of regional climate due to glacial and interglacial periods in the Pleistocene, while human-mediated transportation of pine-wood material might have assisted the relocation and establishment of this pest in novel habitats.

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The multidimensional scaling (MDS) plot based on K2P distances of the 12 populations of T. yunnanensis, with tentative boundary (dash line) between two population groups.
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pone-0111940-g002: The multidimensional scaling (MDS) plot based on K2P distances of the 12 populations of T. yunnanensis, with tentative boundary (dash line) between two population groups.

Mentions: The SAMOVA analysis determined two population groups, with Anning, Luliang, Mengzi, Shilin, Yuxi, and Yanshan comprising one group (Group 1) and Huili, Nanhua, Ninglang, Xichang, Xiangyun, and Zhanyi forming the other (Group 2) (Fig. 1B). The AMOVA verification detected 32.16% of the total variation among the two population groups (FCT  = 0.322, P<0.01), 13.35% among populations within groups (FSC  = 0.197, P<0.01), and 54.49% within populations (FST  = 0.455, P<0.01). For the two groups, genetic variation among populations within Group 2 (24.81%) was greater than that within Group 1 (14.34%) (Table 4). Between the two population groups designated by SAMOVA analysis, the K2P distance was 0.011, pairwise Fst value was 0.344 (P<0.001), Nei's average number of differences was 7.718 (P<0.001), and the Nm value was 0.955. The multidimensional scaling (MDS) plot also divided the 12 populations of T. yunnanensis into two groups, with populations from Anning, Luliang, Mengzi, Shilin, Yanshan, and Yuxi forming one group (Group 1) and that from Huili, Nanhua, Ninglang, Xichang, Xiangyun, and Zhanyi comprising the other (Group 2) (Fig. 2).


Origin and expansion of the Yunnan Shoot Borer, Tomicus yunnanensis (coleoptera: scolytinae): a mixture of historical natural expansion and contemporary human-mediated relocation.

Lü J, Hu SJ, Ma XY, Chen JM, Li QQ, Ye H - PLoS ONE (2014)

The multidimensional scaling (MDS) plot based on K2P distances of the 12 populations of T. yunnanensis, with tentative boundary (dash line) between two population groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221261&req=5

pone-0111940-g002: The multidimensional scaling (MDS) plot based on K2P distances of the 12 populations of T. yunnanensis, with tentative boundary (dash line) between two population groups.
Mentions: The SAMOVA analysis determined two population groups, with Anning, Luliang, Mengzi, Shilin, Yuxi, and Yanshan comprising one group (Group 1) and Huili, Nanhua, Ninglang, Xichang, Xiangyun, and Zhanyi forming the other (Group 2) (Fig. 1B). The AMOVA verification detected 32.16% of the total variation among the two population groups (FCT  = 0.322, P<0.01), 13.35% among populations within groups (FSC  = 0.197, P<0.01), and 54.49% within populations (FST  = 0.455, P<0.01). For the two groups, genetic variation among populations within Group 2 (24.81%) was greater than that within Group 1 (14.34%) (Table 4). Between the two population groups designated by SAMOVA analysis, the K2P distance was 0.011, pairwise Fst value was 0.344 (P<0.001), Nei's average number of differences was 7.718 (P<0.001), and the Nm value was 0.955. The multidimensional scaling (MDS) plot also divided the 12 populations of T. yunnanensis into two groups, with populations from Anning, Luliang, Mengzi, Shilin, Yanshan, and Yuxi forming one group (Group 1) and that from Huili, Nanhua, Ninglang, Xichang, Xiangyun, and Zhanyi comprising the other (Group 2) (Fig. 2).

Bottom Line: Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago.Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one.Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, 650091, China.

ABSTRACT
The Yunnan shoot borer, Tomicus yunnanensis, is a recently-discovered, aggressive pest of the Yunnan pine stands in southwestern China. Despite many bionomics studies and massive controlling efforts, research on its population genetics is extremely limited. The present study, aimed at investigating the origin and dispersal of this important forestry pest, analyzed the population genetic structure and demographic history using a mitochondrial cox1 gene fragment. Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago. Host separation and specialization might have caused the speciation of T. yunnanensis. Genetic structure analyses identified two population groups, with six populations near the origin area forming one group and the remaining six populations from western and eastern Yunnan and southwestern Sichuan comprising the other. Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one. Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan. Our findings implied that T. yunnanensis underwent both historical expansion and recent dispersal. The historical expansion may relate to the oscillation of regional climate due to glacial and interglacial periods in the Pleistocene, while human-mediated transportation of pine-wood material might have assisted the relocation and establishment of this pest in novel habitats.

Show MeSH
Related in: MedlinePlus