Data from: Echoes of a distant time: effects of historical processes on contemporary genetic patterns in Galaxias platei in Patagonia

Interpreting the genetic structure of a metapopulation as the outcome of
gene flow over a variety of timescales is essential for the proper
understanding of how changes in landscape affect biological connectivity.
Here we contrast historical and contemporary connectivity in two
metapopulations of the freshwater fish Galaxias platei in northern and
southernmost Patagonia where paleolakes existed during the Holocene and
Pleistocene, respectively. Contemporary gene flow was mostly high and
asymmetrical in the northern system while extremely reduced in the
southernmost system. Historical migration patterns were high and symmetric
in the northern system and high and largely asymmetric in the southern
system. Both systems showed a moderate structure with a clear pattern of
isolation by distance (IBD). Effective population sizes were smaller in
populations with low contemporary gene flow. An approximate Bayesian
computation (ABC) approach suggests a late Holocene colonization of the
lakes in the northern system and recent divergence of the populations from
refugial populations from east and west of the Andes. For the southern
system, the ABC approach reveals that some of the extant G. platei
populations most likely derive from an ancestral population inhabiting a
large Pleistocene paleolake while the rest derive from a higher-altitude
lake. Our results suggest that neither historical nor contemporary
processes individually fully explain the observed structure and geneflow
patterns and both are necessary for a proper understanding of the factors
that affect diversity and its distribution. Our study highlights the
importance of a temporal perspective on connectivity to analyse the
diversity of spatially complex metapopulations.