How and when did Deschampsia antarctica reach Antarctica?

FASANELLA, MARIANA; ANDREA CECILIA PREMOLI; JUAN DOMINGO URDAMPILLETA; MARÍA LAURA GONZÁLEZ; JORGE OSCAR CHIAPELLA

Kiel

Congreso; The International Plant Science Conference; 2017

Deschampsia antarctica is the only grass with disjunct distribution between Patagonia and Antarctica, and offers a unique model to examine the relative contribution of vicariance and dispersal. While some aspects of Antarctic plants have been extensively studied little is known about the related Patagonian populations; particularly in genetics and cytogenetics. We study the distribution of genetic and chromosomal polymorphisms along the entire range of D. antarctica to unravel its biogeographic history. We collected leaf from 17 populations in Patagonia and 6 in Antarctica and sequenced a total of 144 individuals by nuclear and chloroplast regions. We studied the cytogenetic structure, quantified genetic diversity and structure and tested the divergence time between regions. Patagonia has greater variability in chromosomal and molecular characters over Antarctica. We found a significant divergence between Patagonia and Antarctica (cpDNA Fst = 0.518, p < 0.001; nDNA Fst = 0.823, p < 0.001). The large number of private haplotypes and the great genetic and chromosomal variability found in Patagonia, support the hypothesis of a South American origin of the Antarctic populations of D. antarctica. The divergence time between regions was dated in the Mid-Late Pleistocene and dispersal to Antarctica possibly occurred through bird-aided long-distance transport from South America.