Researchers in Tokyo have identified candidate genes that could enhance fish’s ability to thrive in warmer and saltier water. These findings have the potential to be a valuable resource for freshwater aquaculture breeding programs, especially in a world grappling with the effects of global warming on water quality and availability. The study’s results were recently published in the journal ‘Genomics.’
Freshwater aquaculture is a crucial source of essential nutrients and protein, and one popular species for such farming is Nile tilapia (Oreochromis niloticus). These fish have gained popularity due to their adaptability to various water conditions and production systems.
However, rising global temperatures have led to dwindling freshwater resources, putting pressure on fish farms and the people who depend on them for sustenance. The urgent need is for fish strains that can thrive despite increased salinity and water temperature.
To address this challenge, a team of researchers from the Earlham Institute, the University of East Anglia, and the University of Stirling delved into the tilapia genome. They aimed to identify genetic changes responsible for the species’ increased tolerance to changing water conditions.
The research focused on the gills, a vital organ for osmoregulation in fish, and involved the generation of DNA and RNA sequence data to study gene activity, regulation, and function. The team specifically looked for genetic differences in gene regulatory regions between Nile tilapia and 27 other tilapia species, assuming that these differences could be linked to the fish’s adaptation to varying water environments.
The researchers employed a genome sequencing approach to uncover potential transcription factor binding sites and genetic switches responsible for controlling gene expression. They pinpointed regions of the genome believed to control the activity of osmoregulatory genes, which influence gill function and how the fish responds to changing water conditions.
Several genes relevant to traits that enable tilapia to tolerate saltier water and adapt to freshwater were identified. These genes included those involved in metabolism and essential processes that help the fish maintain balance in response to environmental changes.
Dr. Tarang Mehta, a study author and postdoctoral research scientist at the Earlham Institute, emphasized the importance of these findings for breeders in need of genomic resources to enhance selective breeding programs and develop more resilient fish strains.