LalDin, Asif (2016) The development and application of molecular tools to differentiate 'Dreissena' species. (MSc(R) thesis), Kingston University, .

Abstract

'Dreissena polymorpha' (Pallas 1771) and 'Dreissena bugensis' (Andrusov, 1897) are two species of invasive mollusc bivalves native to the Ponto-Caspian region. They are regarded as some of the most dangerous invasive species in terms of risk of arrival, establishment and detrimental ecological effects. The extent of the species' invasion is largely unprecedented with all continents except Antarctica affected. The United Kingdom has been invaded 'D. polymorpha' which was first recorded in 1824 at the Surrey docks in London and 'D.bugensis' thought to have invaded more recently. Since their arrival the species have placed an immense strain on freshwater ecosystems resulting in significant economic and ecological damage. Species assignment and identification has been a contentious matter with many conflicting reports. Over the last 25 years more focus has been placed on molecular methods of identification as opposed to traditional methods relying heavily on morphological characteristics. Despite extensive work on populations in mainland Europe and North America there no detailed studies on the molecular identification or variation of 'Dreissena' int he UK. Molecular data generated from several sites across London have indicated that that morphological identification of these organisms is largely inaccurate. By using a combination of markers the mitochondrial COI and the nuclear ribosomal internal transcribed region it has been possible to accurately identify 'D.polymorpha' and 'D.bugensis'. Using this approach has not only allowed improved resolution in mussel identification but has also identified the first putative hybrids between 'D.polymorpha' as well as 'D.bugensis', further complicating their taxonomy. The accurate identification of both species allowed for analysis of population genetic structure with local populations; a task not yet undertaken.

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