Genetic diversity in the moss Pohlia nutans on geothermal ground of Mount Rittmann, Victoria Land, Antarctica.

The only known population of the moss Pohlia nutans in continental Antarctica
occurs on geothermally heated ground of volcanic Mt. Rittmann in northern
Victoria Land. Colonization of this bryophyte is due to peculiar environmental
characteristics of the geothermal ground, because mosses do not normally grow
in Antarctica at such elevations. Specimens from several moss patches within
two sites of 80 m2 total area were analyzed genetically to determine whether
they all originated from a single colonization event, whether the population is
genetically diverse and whether the temperature range of geothermal ground
(17-35 degrees C under moss colonies) affects rates of mutation. Both the RAPD
technique and DNA sequencing of the conserved nuclear ribosomal RNA 18S-26S ITS
region were used to compare this extremely isolated population, with specimens
of P. nutans from elsewhere in Antarctica. Like the moss Campylopus pyriformis
on the volcanic Mt. Melbourne, the Pohlia population exhibits low levels of
genetics diversity and appears to be derived from a single immigration event
followed by vegetative grow, mutation and dispersal.