Development of microsatellite markers for Antarctic Bryum Hedw. species

• Main Author: Harfoot, Rhodri T.
• Other Authors: Gemmill, Chrissen E.C.
• Format: Thesis
• Language: English
• Published: The University of Waikato 2019
• Subjects: Antarctic; Antarctic Peninsula; Victoria Land; McMurdo Dry Valleys; Ross Island; Granite Harbour; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/10289/12842

The objective of this thesis was to isolate microsatellite markers using the Glenn (2001) method from the species Bryum argenteum so as to be able to study these markers in Antarctic populations of Bryum species. Microsatellite regions have been found to be highly polymorphic and neutral markers, and usually genus specific, thus making them ideal for population genetic studies. The populations to be studied in the future have a large distribution over the Southern Victoria Land area, ranging from the Dry Valleys to Granite Harbour and Ross Island. Mosses are the most abundant and widespread of the vascular plant groups within continental Antarctica. They inhabit locations that are some of the more extreme on earth and experience periods of desiccation and darkness that can last as long as four months. For these reasons the establishment of mosses in Antarctica is a subject that has attracted great debate. One hypothesis suggests that mosses first became established when the ice retreated from the land approximately 17000 years ago, at the end of the last glacial maximum. The alternative hypothesis is that mosses survived as relictual populations over this period and have recently increased their habitat range. The study of microsatellite length polymorphism in populations will allow these hypotheses to be tested. The genus Bryum Hedw. (Bryaceae) is a highly polymorphic, cosmopolitan genus that is abundant in Antarctica over a wide range of locations. It is found from the Sub-Antarctic zone (Sub-Antarctic islands) to the continental zone (Continental Antarctica and Southern and Eastern Antarctic Peninsula. Thus covering a wide range of habitats from warm and wet (e.g. the Sub-Antarctic islands) to cold and very dry (e.g. the McMurdo Dry Valleys). To study the population genetics of Antarctic Bryum species, development of microsatellite markers was necessary as it has been found that with less specific methods such as RAPD-PCR, the DNA used for the analyses had been contaminated by co-extracted DNA from fungi living on the mosses, thus confounding the results obtained. Microsatellites, once developed, are genus or family specific, thus there is little risk of amplifying a contaminant when using microsatellite markers. Abstract This project failed to isolate any microsatellite markers from Bryum argenteum, due to experimental difficulties that occurred at three major stages; ligation, transformation and hybridisation screening of the genomic library. Future research should be focussed on completion of microsatellite isolation for this genus and on evaluation of the population relationships among Antarctic localities.