Alternative splicing and parallel patterns of gene expression underlie
population and life history divergence in an amphibian
Abstract
Populations distributed across anthropogenic disturbance gradients can
express different phenotypes adapted to distinct habitats. Previous
studies have focused on the role of gene expression linking phenotypic
and genetic variation in wild populations. However, recent studies have
revealed the critical role of post-transcriptional processes such as
alternative splicing in generating phenotypic variation in response to
modified environments. Knowledge of alternative splicing should provide
more comprehensive insights into understanding population responses to
environmental change. Here, we examined gene expression and alternative
splicing patterns in the wood frog, an amphibian known for strong
phenotypic divergence in response to road-adjacency and runoff
pollution. Roadside populations show locally maladaptive traits as
embryos and larvae but adaptive traits as adults, suggesting potential
tradeoffs across life history in response to road effects. Here, we
found strong differences in gene expression and alternative splicing
patterns between hatchlings and adults, along with population specific
patterns. However, only two differentially expressed genes (Hsp70 and
GPSM2) showed repeated divergence between roadside populations and
populations located away from roads. These results suggest that while
local populations and life history stages can diverge substantially in
both gene expression and alternative splicing, a low degree of
transcriptomic parallelism underlies (mal)adaptation to roads and
pollution.