Data from: Lineage divergence, local adaptation across a biogeographic break, and artificial transport, shape the genetic structure in the ascidian Pyura chilensis

Marine benthic organisms inhabit a heterogeneous environment in which
connectivity between populations occurs mainly through dispersive larval
stages, while local selective pressures acting on early life history
stages lead to non-random mortality, shaping adaptive genetic structure.
In order to test the influence of local adaptation and neutral processes
in a marine benthic species with low dispersal, in this study we used
Genotyping by Sequencing technology to compare the neutral and putatively
selected signals (neutral and outlier loci, respectively) in SNPs
scattered throughout the genome in six local populations of the
commercially exploited ascidian Pyura chilensis along the southeast
Pacific coast (24°–42°S). This species is sessile as an adult, has a
short-lived larval stage, and may also be dispersed by artificial
transport as biofouling. We found that the main signal in neutral loci was
a highly divergent lineage present at 39°S, and a subjacent signal that
indicated a separation at 30°S (north/south), widely reported in the area.
North/south separation was the main signal in outlier loci, and the linage
divergence at 39°S was subjacent. We conclude that the geographic
structure of the genetic diversity of outlier and neutral loci was
established by different strengths of environmental, historical and
anthropogenic factors.