ausblenden:
Schlagwörter:
biogeography; freshwater ecology; next generation sequencing; phylogeography; Pleistocene glaciations
Zusammenfassung:
Repeated Quaternary glaciations have significantly shaped the present distribution
and diversity of several European species in aquatic and terrestrial habitats.
To study the phylogeography of freshwater invertebrates, patterns of
intraspecific variation have been examined primarily using mitochondrial
DNA markers that may yield results unrepresentative of the true species history.
Here, population genetic parameters were inferred for a montane aquatic
caddisfly, Thremma gallicum, by sequencing a 658-bp fragment of the mitochondrial
CO1 gene, and 12,514 nuclear RAD loci. T. gallicum has a highly
disjunct distribution in southern and central Europe, with known populations
in the Cantabrian Mountains, Pyrenees, Massif Central, and Black Forest.
Both datasets represented rangewide sampling of T. gallicum. For the CO1
dataset, this included 352 specimens from 26 populations, and for the RAD
dataset, 17 specimens from eight populations. We tested 20 competing phylogeographic
scenarios using approximate Bayesian computation (ABC) and
estimated genetic diversity patterns. Support for phylogeographic scenarios
and diversity estimates differed between datasets with the RAD data favouring
a southern origin of extant populations and indicating the Cantabrian Mountains
and Massif Central populations to represent highly diverse populations
as compared with the Pyrenees and Black Forest populations. The CO1 data
supported a vicariance scenario (north–south) and yielded inconsistent diversity
estimates. Permutation tests suggest that a few hundred polymorphic
RAD SNPs are necessary for reliable parameter estimates. Our results highlight
the potential of RAD and ABC-based hypothesis testing to complement phylogeographic
studies on non-model species.
