Study finds DNA region linked to disease resistance in tilapia

A section of the genetic code in tilapia significantly affects survival during a virus outbreak, leading to potential for breeding resistant fish.

Image credit: Artur Rydzewski on Flickr
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Scientists analysed the genome of almost 1,000 fish from a pond that had experienced an outbreak of Tilapia Lake Virus.

A specific region in the genome of Nile tilapia – a key aquaculture species that is worth nearly $10 billion globally – has a major effect on mortality levels during an outbreak of Tilapia Lake Virus (TiLV), a study led by the Roslin Institute and WorldFish has found.

Fish with specific genetic variants in this region were substantially less likely to die in an outbreak of the virus than fish without these variants. Survival rates improved by approximately one-third, scientists observed.

By selecting parent fish for breeding based on these variants, tilapia strains with innate resistance can be developed. This will reduce the number of outbreaks and mortality rate of TiLV, which is one of the biggest threats to tilapia aquaculture, with mortalities up to 90 percent and for which vaccines are not yet available.

Improved survival
Comparing the genomes of fish that survived the outbreak with fish that did not enabled scientists to find the region in the genome containing variants associated with survival.

The average survival rate of tilapia with the favourable variants was 32 percent higher than that of fish with none of the variants, scientists found.

The study, published in the journal Heredity, was funded by the CGIAR Research Program on Fish Agri-Food Systems (FISH) and the Biotechnology and Biological Sciences Research Council, part of UK Research and Innovation.

For more information visit the University of Edinburgh website, HERE.

The Aquaculturists

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