Scale matters: genome-wide signatures of local adaptation to
high-resolution environmental variation in an alpine plant
Microevolutionary processes shape adaptive responses to heterogeneous
environments, where these effects vary both among and within species.
However, the degree to which signatures of adaptation to environmental
drivers can be detected based on spatial scale and genomic marker
remains largely unknown. We studied signatures of local adaptation
across different spatial extents, investigating complementary types of
genomic variants–single nucleotide polymorphisms (SNPs) and polymorphic
transposable elements (TEs)–in populations of the alpine model plant
species Arabis alpina. We coupled high-resolution (0.5m) environmental
factors, derived from remote sensing digital elevation models, with
whole-genome sequenced data of 304 individuals across four populations.
We demonstrate that responses of A. alpina to similar amounts of abiotic
variation are largely governed by local evolutionary processes and find
minimally overlapping signatures of local adaptation between SNPs and
polymorphic TEs. Notably, functional annotations of high-impact genomic
variants revealed several defence-related genes associated with the
abiotic factors studied, which could indicate indirect selective
pressure of biotic agents. Our results highlight the importance of
considering different spatial extents and types of genomic polymorphisms
when searching for signatures of adaptation to environmental variation.
Such insights provide key information on microevolutionary processes and
could guide management decisions to mitigate negative impacts of climate
change on alpine plant populations.