Genetic variation of mtDNA gene sequences in the collembolan Isotoma klovstadi from Victoria Land, Antarctica: evidence for population differentiation

The extreme Antarctic environment influences the population structure of soil microarthropods, which are often patchily distributed along the deglaciated coasts. As a consequence of the low dispersal capabilities of these organisms, populations are effectively isolated from one another. We tested the effects of the Antarctic environment on the genetic structure of microarthropod populations by analysing mitochondrial COII gene sequences in 40 individuals from 4 distinct populations of the collembolan Isotoma klovstadi collected in Victoria Land. Eighteen different haplotypes were found, 17 of which were only found in single populations. Information derived from the number of haplotypes and their sequence divergence suggests that the populations from Cape Jones and Crater Cirque are the most uniform. We conclude that, although gene flow might have been higher in the past, populations of I. klovstadi are presently quite isolated from one another, providing potentially suitable conditions for microspeciation processes.