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キーワード:
DGE; EST; Gasterosteus aculeatus; local adaptation; three-spined stickleback; transcriptome sequencing
要旨:
Understanding the extent of local adaptation in natural populations and the mechanisms
that allow individuals to adapt to their native environment is a major avenue in
molecular ecology research. Evidence for the frequent occurrence of diverging ecotypes
in species that inhabit multiple ecological habitats is accumulating, but experimental
approaches to understanding the biological pathways as well as the underlying genetic
mechanisms are still rare. Parasites are invoked as one of the major selective forces
driving evolution and are themselves dependent on the ecological conditions in a
given habitat. Immunological adaptation to local parasite communities is therefore
expected to be a key component of local adaptation in natural populations. Here, we
use next-generation sequencing technology to compare the transcriptome-wide
response of experimentally infected three-spined sticklebacks from a lake and a river
population, which are known to evolve under selection by distinct parasite communities.
By comparing overall gene expression levels as well as the activation of functional
pathways in response to parasite exposure, we identified potential differences between
the two stickleback populations at several levels. Our results suggest locally adapted
patterns of gene regulation in response to parasite exposure, which may reflect different
local optima in the trade-off between the benefits and the disadvantages of mounting
an immune response because of quantitative differences of the local parasite
communities.
