Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/5408
This project is a study of variation in two nuclear markers in two arthropods (Crangonyx islandicus and Apatania zonella). Both species have been found to have highly divergent mtDNA lineages within Iceland.
Crangonyx islandicus is an endemic groundwater amphipod species recently discovered in Iceland. Based on variation in mtDNA genes, COI and 16S RNA, Kornobis et al, (2010) concluded that this species had survived glaciations periods in sub-glacial refugia. The mtDNA variation defined several monophyletic groups, restricted to different geographic regions in Iceland and which have diverged in Iceland for up to 4 – 5 Million years. This was supported by a correlation between genetic and geographic distances among species. In this study we look at the internal transcribed spacer (ITS) gene, a piece of non-functional RNA situated between structural ribosomal RNAs (rRNA).
The results show different patterns from the mtDNA results in Kornobis et al. (2010), with a major split between two populations, between north and southern Iceland, and different partition among samples in southern populations. The main difference is characterized by a large size difference of the ITS1 region due to insertion or deletion, a highly variable microsatellite was funs within this region.
The second part of the project is based in the study of Apatania zonella, a caddisflie (Trichoptera), a circumpolar species which lives at high latitudes, in cold-clear water, streams, lakes and marshes.
This study is a continuation of a previous study “Mitochondrial variation of the caddisflies Apatania zonella and Potamphylax cingulatus” (Sanz, 2010). The former study showed that Iceland acts as a zone of admixture, where two populations of A. zonella with distinct mtDNA types have arrived, from both ends of its range distribution, one from North America and the other from Europe. In this study we use a nuclear marker, EF alpha, in order to know whether the structure obtained by mtDNA in North America and Europe, is reflected in a nuclear marker and also to verify whether individuals in Iceland of different geographic origin as defined by mtDNA have interbred in Iceland.
The results show less clear structure with EF alpha than found in mtDNA. Populations could be sexual or asexual depending on the country. Moreover, results show the rate of evolution of EF alpha is slower than COI’s rate.
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