Genetic Clues Uncovered in Tilapia's Fight Against Deadly Virus

Tilapia Lake Virus (TiLV) is a major threat to Nile tilapia, a vital species for global aquaculture. To protect these fish, scientists are searching their DNA for the secrets to natural resistance.

In a large-scale study, researchers analysed the genomes of tilapia that survived a natural TiLV outbreak. Their work confirmed a key genetic region, known as a quantitative trait locus (QTL), on chromosome Oni22 that is strongly linked to survival. They pinpointed the most influential genetic markers within this region, narrowing the search for the core of this defensive trait.

However, resistance is not a one-gene show. The analysis revealed other genetic markers on different chromosomes also play a significant role. This points to an "oligogenic" architecture, where resilience arises from the combined action of several genes with moderate effects and many with smaller ones. Two specific genes, psmb9a and ha1f, were highlighted as potential causal candidates.

These discoveries provide crucial markers for breeding programmes. By selecting for these traits, we can cultivate hardier tilapia, improving fish welfare and the security of a global food source.