Every specimen carries its own set of genes and by studying these genes we get insight in the ancestral tree of that specimen. Depending on the genes studied and techniques used we can look into the near or farther past. In this study, researchers from Belgium, UK and Italy looked at the mitochondrial DNA from stag beetles at 121 European locations. The resembles of the genetic patterns at these locations tells us something about the colonization of this species after the last ice age. The results show two clear groups in Europe, one group is found in Greece and the other one is found all over Europe. Based on this, they could confirm that a group of stag beetles survived in Greece during the last ice age, but since then this population has not colonized any new territory. The other population, however, shows clear patterns of recent and rapid range expansion after the last ice age. The origin of this population lies in central Italy. This means that quickly after the last ice age, these stag beetles were able to cross the Alps and then spread out to entire Europe up to the Ural Mountains, about 3500 km from their starting point in central Italy.
More info: Cox K, McKeown N, Antonini G, Harvey D, Solano E, Van Breusegem A & Thomaes A (2019) Phylogeographic structure and ecological niche modelling reveal signals of isolation and postglacial colonisation in the European stag beetle. PLoS ONE, 14(4): e0215860