The project aims to examine the effects of latitudinal temperature change on muscle function in amphipod crustaceans. As temperature has a profound effect on the ability of muscles to contract and produce force/power for movement, we are interested to see if there is any compensation for the effects of temperature between amphipod populations living at different latitudes. To this end we are studying Gammarid amphipod species due to their wide geographical distribution along the coast of North West Europe from temperate conditions in the Northern Atlantic (at approx 15°C in the summer) to polar conditions in the Arctic (at -1°C in the summer). In particular we are interested in the effects of temperature gradients on heavy chain myosin genes, as these genes regulate critical aspects of muscle contraction and can be influenced by changes in environmental temperature by switching from one gene variant to another. During our visit to Ny-Ålesund we hope to collect at least 3 different species of gammarid amphipod, including Gammarus locusta, G. zaddachi, and G. oceanicus to represent populations from the northerly limit of their latitudinal range. The muscle tissue will then be examined for sequence variations in specific active regions of the myosin genes that are known to influence the production of force. Sequence variation will be compared to the data collected from populations in the UK and in Tromso, Norway (70N). Ultimately the results will be correlated to the genetic diversity of the amphipod populations to assess the evolution of myosin genes in animals with a wide distribution pattern and inherent adaptability to temperature change.