RAPD Analysis of East Antarctic Pottia heimii Populations

Abstract

Pottia heimii contributes significantly to the sparse terrestrial vegetation in East Antarctica, especially within the Dry Valley region. Using Randomly Amplified Polymorphic DNA (RAPD), levels of genetic variation were investigated in several East Antarctic P. heimii populations. The initial stage of the study optimised the RAPD protocol specifically for antarctic P. heimii. RAPDs gave similar profiles for genetically identical P. heimii tissue (shoots joined at the base) and were able to detect DNA differences between individual shoots within a moss clump, confirming the usefulness of RAPDs for P. heimii population studies. Genetic distance matrices calculated from RAPD banding patterns were presented as dendrograms and used in an Analysis of Molecular Variance (AMOV A). Using single moss shoots, a significant level of genetic variation was detected within three 50 metre transects collected in the Miers Valley. The genetic spatial structure within these transects was random indicated by the distribution of genotypes. This suggested wind was the most likely agent for local propagule dispersal. No genetic subdivision existed between the transects, therefore individuals could be considered to be taken from a single population. Comparison of individuals from Miers Valley, East Garwood Valley, Bratina Island and Edmonson Point showed the first three Southern Victoria Land populations could be considered as a single larger population genetically distinct from the more northerly Edmonson Point population. The level of genetic variation within all the East Antarctic P. heimii populations analysed was considered significant.