RAPD ANALYSIS OF GENETIC-VARIATION AND DISPERSAL OF THE MOSS BRYUM-PSEUDOTRIQUETRUM FROM SOUTHERN-VICTORIA-LAND, ANTARCTICA

The RAPD technique (Random Amplified Polymorphic DNA) was used to asse ss the level of genetic diversity in Bryum pseudotriquetrum from South ern Victoria Land, Antarctica. Isolates were collected from two transa cts, and from several other geographically distinct populations within 150 km of Ross Island. Moss growth in one transect, sampled down a sm all exposed meltstream channel at Cape Chocolate, was very sparse with no other moss colonies found within several hundred meters. Isolates from this transect showed low levels of genetic variation, with many m oss clumps appearing identical; these were probably dispersed by water along the channel. In another transect analysed from Granite Harbour, the moss colonies were large, luxuriant and protected by boulders. Th ese isolates showed considerably higher levels of genetic variability than the Cape Chocolate samples, and both within and between-clump var iation was observed. Samples from other sites showed varying levels of genetic diversity. It appears from these results that the degree of p rotection from the harsh Antarctic environment can influence not only the type of moss growth, but also the level of genetic diversity. Evid ence is presented for both short-distance dispersal by water and long- distance dispersal by wind.