@article {9058,
	title = {Pitfalls in applying mitochondrial markers onto the scolytid species Pityogenes chalcographus},
	journal = {U S Forest Service Rocky Mountain Research Station Proceedings RMRS-P},
	volume = {45},
	year = {2007},
	month = {June},
	pages = {15-19},
	abstract = {Pityogenes chalcographus is one of the major pests in Eurasian spruce stands. Crossing experiments performed in the mid-1970s suggested race differentiation, and mtDNA analysis of P. chalcographus gave evidence that today{\textquoteright}s populations are divided into several clades. The genetic distance between clades favours a model of allopatric origin with a separation about one million years ago while today haplotypes of the major clades exist sympatrically all over Europe. Within the last few years, the use of mtDNA as a sole genetic marker became a matter of critical discussion. It was shown that nuclear copies of mtDNA (numts) led to artefacts in some of the derived genealogies. A long PCR based approach for elimination of potential numt sequences was developed to validate the dataset of P. chalcographus. This method showed that the beetle{\textquoteright}s genome does not contain numts. Another factor that may influence mitogenomes is the presence of endosymbiotic Wolbachia, which causes alterations in insect reproduction and thus influences the population{\textquoteright}s mtDNA patterns. While Wolbachia was not found in P. chalcographus in past studies, the use of long and nested PCR, cloning and sequencing of PCR products, and in situ hybridization techniques gave evidence that at least a certain percentage of European populations harbour this intracellular endosymbiont. An influence on the mitochondrial dataset can not be excluded and further research is proposed to estimate the prevalence of Wolbachia in P. chalcographus.},
	keywords = {Pityogenes chalcographus},
	author = {Arthofer, Wolfgang and Avtzis, Dimitrios N. and Riegler, Markus and Miller, Wolfgang J. and Stauffer, Christian}
}
@article {5617,
	title = {Mitochondrial phylogenies in the light of pseudogenes and Wolbachia: re-assessment of a bark beetle dataset},
	journal = {Zookeys},
	volume = {56},
	year = {2010},
	note = {(Special Issue)},
	month = {2010},
	pages = {269-280},
	abstract = {Phylogenetic studies based on mtDNA become increasingly questioned because of potential pitfalls due to mitochondrial pseudogenes and mitochondrial selective sweeps. While the inclusion of nuclear markers should preferentially be considered for future studies, there is no need to abandon mtDNA as long as tests for the known mtDNA artefacts are performed. In this study we present additional data and test previous phylogeographical studies of Pityogenes chalcographus. We did not detect nuclear copies (numts) of the previously used mitochondrial markers by performing a combined long range/nested PCR of the COI gene and by an in silico analysis of the COI sequence data. This confirms the robustness of our previous phylogenetic study of P. chalcographus. Results of an in-situ hybridization of Wolbachia in P. chalcographus confirm the presence of this endosysmbiont in this species. However, we did not detect a correlation between infection status, geographical region and mtDNA haplotypes. The hybridisation data also support a previous hypothesis that infections do not result from parasitoids or parasitic nematodes, insect surface or laboratory contaminations and are hence a true infection of P. chalcographus. We conclude that the deep structure found in mitochondrial populations of P. chalcographus indeed represents the evolutionary history of European populations.},
	keywords = {Pityogenes chalcographus},
	url = {http://pensoftonline.net/zookeys/index.php/journal/issue/view/58},
	author = {Arthofer, Wolfgang and Avtzis, Dimitrios N. and Riegler, Markus and Stauffer, Christian}
}
