Summary
Bryum argenteum sensu lato is a cosmopolitan moss found in many countries of the world, and is one of only a few moss species present in continental Antarctica. We have used RAPD (Random Amplified Polymorphic DNA) technology to investigate how this moss has colonised and spread in Antarctica, and whether it is genetically similar to other populations in nearby temperate land masses. Our modified RAPD technique gave reproducible results for single 2 mm moss shoots; within-clump variation was observed in most isolates, making the use of single shoots essential for these studies. A comparison of B. argenteum isolates from continental Antarctica, as well as from locations in Australia and New Zealand revealed that isolates from Australia and New Zealand are more similar to each other than either population is to the isolates from Antarctica. The level of genetic variation was as high within Antarctic clumps as in those from more temperate regions, even though sexual reproduction has not been observed in the Antarctic populations.