Decoding how fishes respond to environmental change
In the face of environmental change, animals can alter their physiology to cope with new conditions in the short term (plasticity), or natural selection can cause evolution in response to sustained change over multiple generations (adaptation). Understanding how and under what circumstances plasticity and adaptation occur is key to predicting the future persistence and distribution of animal populations under global climate change.
Ribonucleic acid (RNA) is the transcribed form of DNA, an intermediary molecule between hereditary material and proteins. Like DNA, RNA is a strand or sequence. By decoding the RNA sequence in animals in different environments we can determine which genes are being expressed and by how much, providing a snapshot of the physiological response to the environment at the molecular level. Unlike previous techniques for measuring gene expression (e.g., microarrays), RNA sequencing (RNA-seq) does not require any previous knowledge about the genome. Increasingly, RNA-seq is being used to learn about understudied, non-model species, such as the diverse array of marine and freshwater fishes experiencing global climate change.
In our paper, we reviewed studies that used RNA-seq to investigate the responses of fishes to key environmental variables affected by climate change: temperature, salinity, dissolved oxygen concentration, and acidification. Studies exposing fishes to short- and long-term environmental challenges found RNA signatures that revealed energy usage and processes involved in protecting cells from damage changed under stressful conditions. RNA-seq data from laboratory and field studies showed that fishes can have different coping mechanisms (e.g., metabolic shifts, immune responses) and abilities to recover from environmental stress depending on the magnitude and direction of environmental change and the specific adaptations of species and populations. These RNA-seq studies also reveal how environmental change can affect gene expression later in life and in the next generation by modifying the way expression is regulated.
We discuss experimental, analytical, and conceptual challenges surrounding this field and aim to inspire others to use RNA-seq to investigate responses to environmental change in non-model species, such as fishes, that have ecological and socioeconomic importance and potential for use in medical research.
Read the full paper — Transcriptomic responses to environmental change in fishes: Insights from RNA sequencing by Rebekah A. Oomen and Jeffrey A. Hutchings on the FACETS website.
