Abstract
RNA-sequencing has provided a new way to study transcriptomic population differences of non-model organisms such as marine invertebrates. Importantly, population transcriptomics can provide insight regarding the genetic mechanisms that allow some populations to tolerate various environmental stressors in this era of climate change. Such studies can help us predict future population dynamics and species survival for marine invertebrates of ecological and economic value. Here, I review practical considerations for marine invertebrate researchers using RNA-sequencing, recent applications of population transcriptomics in marine invertebrates, current limitations of this approach, and future areas of study.Recent marine invertebrate studies have examined population-specific responses to abiotic stressors including temperature, salinity, pH, and water quality. Populations tolerant of environmental stressors generally show high constitutive gene expression before stress exposure and a muted overall transcriptional response following stress exposure. Evidence for molecular signatures of selection on several genes including ATP synthase and aquaporins has been identified in marine invertebrate populations exposed to broad temperature regimes. At present, the genetic mechanisms underlying individual variation within a population and the transcriptome response to multiple environmental stressors remain poorly understood.Complete assessment of marine invertebrate population responses to climate change will require pairing RNA-sequencing approaches with complementary phenotype studies. Improvements in transcriptome annotation and future work investigating gene expression regulation will lead to an increased understanding of the genes responsible for population-level tolerance to environmental stressors.