RAPD analysis of genetic variation and dispersal of the moss Bryum argenteum in Ross Island and Victoria Land, Antarctica

The Random Amplified Polymorphic DNA technique was used to assess the level of genetic diversity in Bryum argenteum from Ross Island and southern Vict oria Land, Antarctica. Samples were collected from three separate transects , and from other geographically distinct populations within 150 km of Ross Island. Moss growth in two transects, sampled down small exposed meltstream channels at Cape Royds and Cape Chocolate, was very sparse with no other m oss colonies found within 0.4 or 4 km, respectively. However, samples from these channels showed similar levels of genetic variation to those from a t ransect at Granite Harbour, where moss colonies were large, luxuriant and t urf-like between boulders. In all transects, high levels of genetic diversi ty were apparent both within and between colonies, and some spatial relatio nships were observed down the length of the channels? with more extensive v ariation at the top than the bottom of two transects. Samples from other si tes in the region showed varying but high levels of genetic diversity; over all, the majority showed some clustering according to site of collection, w ith short-distance dispersal of propagules by water and transmission betwee n sites presumably by wind. The extensive genetic diversity observed appear s mainly due to somatic mutation within colonies, with some contribution by immigration of propagules from elsewhere into established colonies.