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- Bergh, Jan-Erik, et al.
(author)
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Insect DNA Exposed to Two Insecticides
- 2007
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In: International Conference Directions in Preventive Conservation Sibiu. - Sibiu, Rumänien.
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Conference paper (other academic/artistic)abstract
- Analyses of DNA is now a standard method in exploring taxonomical relationships between taxa or when studying intraspecific genetic variation. For these purposes museum specimen are often used. During their “museum history”, biological collections often have been treated with various insecticides to avoid museum pest attacks. There is a risk that some insecticides have more or less destroyed the specimen DNA, and thus it is important to know to what extent this happens to be able to estimate if old collection are useful for DNA screening and also to avoid future mistakes. Kigawa et al. (2003) showed that methyl bromide, methyl bromide/ethylene oxide (mixed), ethylene oxide, propylene oxide and methyl iodide all caused degradation of DNA in samples of mushroom and chicken muscle. We have tested possible negative effects on insect DNA from exposure of paradichlorobenzene and diclorvos. Species used were Schistocerca gregaria (Orthoptera), Musca domestica (Diptera), Dermestes hemeroidalis (Coleoptera), Periplaneta americana (Blattodea). The specimens were cut into two parts before completely dried in silica gel in closed containers for about 2 weeks. Three serials were set up in sealed, small glass containers for each species: (1) paradichlorobenzene (0.5g ±0.02g, representing saturated concentration); (2) diclorvos (0.5g ±0.02g, representing saturated concentration); and (3) no chemicals (blank). Each serial was sampled after 1 and 4 weeks. Immediately after sampling, the insect tissues were exposed to clean air for 8 hours in order to eliminate chemicals from the tissue before subsequent treatment. Together with the blank samples, the exposed tissues were stored in deep freezers before extracted for DNA after the last tissue sampling. After extraction, a 658 bp (base pair) COI gene fragment of the DNA was amplified using the forward and reverse primers HCO2198 (TAA ACT TCA GGG TGA CCA AAA AAT CA) and HCOout (CCA GGT AAA ATT AAA ATA TAA ACT TC), respectively. Electrophoresis of the PCR products was run for about 2h and presence or absence of the amplified COI gene fragment showed as band or absence of band in UV light. The gel was photographed for documentation of the results. For S. gregaria we did not obtain any clear results, probably because the primer did not work for the COI gene of this species. For the other three species no effect could be seen from the exposure of paradichlorobenzene, while dichlorvos destroyed the COI gene fragment after 28 days. For M. domestica a band was present after one week exposure. Our conclusion is that dichlorvos has a deteriorating effect on DNA. A more extensive experimental series on M. domestica has been started at the Swedish Museum of Natural History. Reference: Kigawa, R., Nochide, H., Kimura, H. and Miura, S., Effects of various fumigants, thermal methods and carbon dioxide treatment on DNA extraction and amplification: A case study on freeze-dried mushroom and free-dried muscle specimens. Collection Forum 2003, 18 (1-2): 74-89.
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| 2. |
- Johanson, K.A., et al.
(author)
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Testing the monophyly of the New Zealand and Australian endemic family Conoesucidae Ross based on combined molecular and morphological data (Insecta: Trichoptera: Sericostomatoidea)
- 2009
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In: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 38:6, s. 563-573
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Journal article (peer-reviewed)abstract
- Conoesucidae (Trichoptera, Insecta) are restricted to SE Australia, Tasmania and New Zealand. The family includes 42 described species in 12 genera, and each genus is endemic to either New Zealand or Australia. Although monophyly has been previously assumed, no morphological characters have been proposed to represent synapomorphies for the group. We collected molecular data from two mitochondrial genes (16S and cytochrome oxidase I), one nuclear gene (elongation factor 1-alpha) (2237-2277 bp in total), and 12 morphological characters to produce the first phylogeny of the family. We combined the molecular and morphological characters and performed both a maximum parsimony analysis and a Bayesian analysis to test the monophyly of the family, and to hypothesize the phylogeny among its genera. The parsimony analysis revealed a single most parsimonious tree with Conoesucidae being a monophyletic taxon and sistergroup to the Calocidae. The Bayesian inference produced a distribution of trees, the consensus of which is supported with posterior probabilities of 100% for 15 out of 22 possible ingroup clades including the most basal branch of the family, indicating strong support for a monophyletic Conoesucidae. The most parsimonious tree and the tree from the Bayesian analysis were identical except that the ingroup genus Pycnocentria changed position by jumping to a neighbouring clade. Based on the assumption that the ancestral conoesucid species was present on both New Zealand and Australia, a biogeographical analysis using the dispersal-vicariance criteria demonstrated that one or two (depending on which of the two phylogenetic reconstructions were applied) sympatric speciation events took place on New Zealand prior to a single, late dispersal from New Zealand to Australia.
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