Pig genes successfully edited to resist African Swine Fever

February 26, 2016

New research has been published showing how a team of scientists has successfully used advanced genetic techniques to produce pigs that are potentially resilient to African Swine Fever — a highly contagious disease that kills up to two-thirds of infected animals.

As described in Science Daily, the new pigs carry a version of a gene that is usually found in warthogs and bush pigs, which researchers believe may stop them from becoming ill from the infection, which is spread by ticks.

When standard farmed pigs are infected with the disease, they quickly become ill and die, but warthogs and bush pigs show no disease symptoms when infected, the article states.

Because of this, the research is focused on one of the pig genes associated with African Swine Fever Virus infection called RELA. The gene causes the immune system to overreact once it detects the disease and can have devastating effects immediately.

Warthogs and bush pigs, however, carry a different version of the RELA gene and scientists believe that this variant — known as an allele — may dampen their immune response and explain why they are more resilient to African Swine Fever compared to farmed pigs.

The article explains that researchers at the University of Edinburgh's Roslin Institute used a gene-editing technique to modify individual letters of the pigs' genetic code. By changing just five letters in their RELA gene, they converted it to the allele that is found in the warthog.

This work builds on previous research from the team, which used similar techniques to produce pigs with a single letter of their genetic code altered. These animals produce a shorter version of RELA. The researchers said this latest study marks the first time researchers have successfully swapped alleles in an animal's genetic code using gene editing.

Scientists will now conduct controlled trials to test whether the genetic changes have improved the pigs' resilience to the disease which is an endemic in Sub-Saharan Africa and some areas of Russia. While the disease has been a serious problem in many African countries, changes in production practices and increasing globalization have also increased the risk of its introduction into other regions.

Past outbreaks have occurred in Europe, South America, the Caribbean, and other areas — devastating pig populations and raising concerns amongst farming groups that it could continue to spread and have a massive impact on food security.

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Category: Food Safety, Animal Safety, Genomics