Towards a thousand sequence ichneumonid wasp molecular phylogeny (Insecta: Hymenoptera: Ichneumonidae) based on the 28S rDNA D2-D3 region
Quicke, Donald L.J.; Laurenne, Nina M.; Fitton, Mike G.; Broad, Gavin R.. 2007 Towards a thousand sequence ichneumonid wasp molecular phylogeny (Insecta: Hymenoptera: Ichneumonidae) based on the 28S rDNA D2-D3 region. Journal of Insect Science, 7. 17-19.Full text not available from this repository.
There is an inevitable trade-off in molecular phylogenetics between the number of genes sequenced and the number of taxa sampled. While having multiple gene fragments to analyse for all taxa would be ideal, the practicality is that seldom do universal primers work on all taxa and for rare species that may only be available from old preserved specimens, DNA degradation means that only multi-copy genes are generally amplifiable. Because of these constraints there has been considerable debate and experimentation over whether it is better to add characters or taxa to a matrix in terms of the accuracy of the final phylogenetic reconstructions, and as far as there is a consensus view, adding taxa, especially ones that help break long branches, appears to have the greater beneficial effect. Our effort has been focused on obtaining a robust molecular phylogeny for the huge parasitic wasp family Ichneumonidae, which has more than 23,000 described species but with an actual species richness ventured to be well in excess of the 60,000 estimated by Townes. Given its size we could not attempt full coverage, but we have tried to get samples from as many different and informative lineages as possible and to sequence these for a single gene fragment initially, the D2-D3 variable region of the nuclear 28S rDNA gene which has been shown to contain a great deal of phylogenetic information within the Ichneumonoidea, despite issues with character alignment (homology). Our current data set comprises over 1000 sequences representing approximately 600 named genera. Some groups such as the Pimplinae show rather little sequence variation, and in analyses this group shows little phylogenetic structure. In contrast, great sequence diversity has been discovered within some genera, notably Mesochorus Gravenhorst (Mesochorinae) and Orthocentrus Gravenhorst and other genera of Orthocentrinae. The data set is being analysed using a wide range of gap opening and gap extension parameters in Clustal X and the resulting alignments analysed using the programme TNT. We hope the resulting molecular phylogenies will stimulate further work on this family including combined molecular and morphological studies. It provides a clear, if not fully resolved, framework for future work, and importantly highlights groups for which acquisition of additional data (mainly additional genes but also various critical taxa) are a priority.
|Programmes:||CEH Programmes pre-2009 publications > Biodiversity|
|CEH Sections:||_ Biological Records Centre|
|NORA Subject Terms:||Biology and Microbiology|
|Date made live:||05 Sep 2007 15:31|
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