Warming waters alter gene expression in fish embryos, affecting their ability to cope with future climate change

Scientists from the University of Manchester delved into the effects of warmer waters on the gene expression of four common fish species. The research focused on the small-spotted catshark, zebrafish, European seabass, and three-spined stickleback. The findings, which have been published in the journal Science of The Total Environment, shed light on the profound changes in gene expression that occur when developing fish embryos are exposed to elevated temperatures.

While the scientific community was already aware of the direct physiological stress that warming rivers and oceans impose on fish, this study goes further by revealing the far-reaching impact on the gene expression patterns of these fish as they mature into adults. This insight has potentially significant implications for the fish’s ability to navigate and respond to future fluctuations in temperature, thereby influencing their chances of survival in the face of ongoing climate change.

Notably, the researchers were unable to identify consistent differentially expressed genes that could be directly linked to the biological changes triggered by global warming. However, the University of Manchester’s analysis points toward the possibility that distinct changes in phenotype during later stages of life may arise due to alterations in the organization of the transcriptome—the essential genetic code as it is interpreted and executed.

The study employed advanced modeling techniques, revealing that fish that experienced developmental warming exhibited increased disorder in the way genes interact, leading to a less structured and potentially more random set of gene interactions. Professor Holly Shiels from the University of Manchester stressed the importance of comprehending how climate change affects an animal’s biological capacity to respond to future environmental challenges, given the looming threat it poses to various species.

Dr. Dan Ripley, also from the University of Manchester, emphasized the study’s indication that exposure to higher temperatures during embryo development could impact a fish’s ability to tackle challenges it may encounter later in life. Dr. Adam Stevens, another contributor to the research, highlighted the discovery that developmental warming altered gene relationships, essentially changing the “plumbing” of the system and consequently affecting its functioning in adulthood. This change was absent in fish reared under control conditions.

In the study, fish embryos were subjected to either control conditions representing current everyday temperatures or warmer treatment conditions simulating future scenarios under climate change. After the embryonic phase, all fish were transitioned to control conditions, mirroring the movement of adult fish in the wild as they seek areas with their preferred temperature range.

Interestingly, despite residing in their preferred temperature range during adulthood, genetic differences were detected between the groups based on the temperatures experienced during their embryonic development. These genetic distinctions were linked to an altered capacity to respond to future warming events as adults, suggesting that early-life conditions have a lasting impact on the fish’s ability to cope with environmental changes.

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