A collaborative effort that includes the Earlham Institute, the Roslin Institute, and WorldFish has produced the first full, high-quality reference genome for a genetically improved tilapia. This fundamental resource will benefit fish breeders looking to develop strains that grow bigger, grow quickly, and have improved resilience to the environmental challenges of a warming planet.
The Genetically Improved Farmed Tilapia (GIFT) program, spearheaded by WorldFish, has produced one of the elite tilapia strains found today and distributed worldwide, achieved through selective breeding without a complete reference genome. To accelerate the development of improved GIFT strains through genomic selection, researchers at the Earlham and Roslin Institutes worked to generate a near-complete and high-quality reference genome from tissues provided by WorldFish. The genome was then annotated, using a cutting-edge approach developed by the Swarbreck Group at the Earlham Institute.
The GIFT strain was originally developed from a combination of commercial and wild Nile tilapia strains, as well as crosses with other species. By using the genomes of closely-related species, including Oreochromis mossambicus (Mozambique tilapia) and O. aureus, they were able to reveal the extent to which genetic material may have passed between species in the past - and identify the specific regions in the GIFT genome. They found more than 11 million bases of O. mossambicus genomic material within the GIFT genome, including genes associated with immunity and growth rate. Their discovery will be useful in future breeding programs.