by Mark Clements, WATTPoultry magazine
Areas of chicken DNA that may influence natural resistance to highly pathogenic avian influenza have been identified by a team of scientists at the U.K.’s Roslin Institute, offering a first step toward breeding chickens with greater resistance.
The Roslin team, working with partners Hy-line International (USA) and colleagues in Warsaw, Poland and Iowa State University, USA, analyzed DNA from chickens that had survived an HPAI outbreak in 2015, and compared it with that of uninfected, presumed-susceptible birds, looking for differences that could reveal genes linked to resistance.
by Mark Clements, WATTPoultry magazine
The results have revealed specific regions across nine diffident areas of the chicken genome where genetic variations appeared to play a role.
Although no single gene fully explained why some chickens survived, the study pinpointed several genes likely associated with the immune system and the bird’s response to the virus. The chickens studied survived a particularly lethal avian flu outbreak, with a mortality rate of over 99%.
Some of the genes identified in these chickens, including one known as ANP32A, are already known to play a role in how animals respond to bird flu. The presence of a gene with a known role in viral resistance supports the idea that the other newly identified genes may also be relevant in defending against bird flu.
Dr. Jacqueline Smith, genome scientist at the Roslin Institute said: “Chickens are extremely vulnerable to highly pathogenic strains of avian flu, so being able to examine DNA from a few birds that survived provides us with a unique opportunity to try to understand the genetics’ underlying resistance.”
She continued that the research offered a first look at how host response may enable birds to fight off infection, something that is only now beginning to be understood.
Building on ANP32A discovery
In 2023, Roslin’s scientists announced what they described as an encouraging first step forward in gene editing techniques to restrict avian influenza viruses from infecting chickens. While the results were encouraging, further gene edits would be needed, they said, to produce a chicken population that could not be infected by avian influenza.
The team found, however, that by changing part of a small section of a chicken’s DNA, they were able to restrict, but not completely block, the virus from entering chickens, with no impact on bird health or wellbeing.
Working with scientists from Imperial College London and the Pirbright Institute, they bred chickens with alterations to the section of chicken’s DNA responsible for producing the ANP32A protein, which is hijacked by influenza viruses to replicate themselves.
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