hide
Free keywords:
climate modeling; genomic analysis; range expansion; spider; transcriptomic analysis
Abstract:
Poleward range expansions are commonly attributed to global change, but could alternatively be
driven by rapid evolutionary adaptation. A well-documented example of a range expansion during the past decades is provided by the European wasp spider Argiope bruennichi. Using ecological niche
modeling, thermal tolerance experiments and a genome-wide analysis of gene expression
divergence, we show that invasive populations have adapted to novel climatic conditions in the
course of their expansion. Their climatic niche shift is mirrored in an increased cold tolerance and a
population-specific and functionally differentiated gene expression response. We generated an
Argiope reference genome sequence and used population genome re-sequencing to assess genomic
changes associated with the new climatic adaptations. We find clear genetic differentiation and a
significant admixture with alleles from East Asian populations in the invasive Northern European
populations. Population genetic modeling suggests that at least some of these introgressing alleles
have contributed to the new adaptations during the expansion. Our results thus confirm the notion
that range expansions are not a simple consequence of climate change, but are accompanied by fast
genetic changes and adaptations that may be fuelled through admixture between long separated
lineages.
