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

The extreme Antarctic environment influences the population structure of so il microarthropods, which are often patchily distributed along the deglacia ted coasts. As a consequence of the low dispersal capabilities of these org anisms. populations are effectively isolated from one another. We tested th e effects of the Antarctic environment on the genetic structure of microart hropod populations by analysing mitochondrial COII gene sequences in 40 ind ividuals from 4 distinct populations of the collembolan Isotoma klovstadi c ollected in Victoria Land. Eighteen different haplotypes were found. 17 of which were only found in single populations. Information derived from the n umber of haplotypes and their sequence divergence suggests that the populat ions from Cape Jones and Crater Cirque are the most uniform. We conclude th at. although gene flow might have been higher in the past, populations of I . klovstadi are presently quite isolated from one another. providing potent ially suitable conditions for microspeciation processes.