Genetic diversity in the moss Hennediella heimii in Miers Valley, southernVictoria Land, Antarctica

The moss Hennediella heimii constitutes a significant proportion of the ter restrial flora of East Antarctica, especially in the McMurdo Dry Valleys re gion of southern Victoria Land. This is the first investigation of the exte nt of genetic variation within a population of H. heimii Random Amplified P olymorphic DNA has been used to study both genetic diversity and dispersal of this moss in Miers Valley, southern Victoria Land. The results showed th at genetic variation does occur in H. heimii (possibly due to increased exp osure to UV-B irradiation), even between shoots within single colonies. and that colonies collected from three transects along meltstreams within the valley constitute a single large population. However, comparison with sampl es of the same species from nearby valleys and sites up to 500 km distant s howed that the Miers Valley population is distinct from these other populat ions. The results also indicate that wind plays a major role in dispersal o f H. heirmii in this region of Antarctica.