After 22 years of creating “Dolly-The Cloned Sheep” at Roslin Institute, British scientists are now developing gene-edited chickens engineered to be completely resistant to flu. The first batch of the transgenic chicks will be hatched later this year. This mission is a new approach in trying to put an end to the next deadly human virulent disease.
“The first of the transgenic chicks will be hatched later this year at the Roslin Institute at the University of Edinburgh in Scotland”, said Wendy Barclay, a professor of virology at Imperial College London responsible in co-leading the project.
The fowls’ DNA is being engineered using a new gene editing technology known as CRISPR. In this research the ‘tagged genes’ of a protein are to be removed in which the flu virus normally depends, and placed by altered gene making the chickens totally flu-resistant.
“The idea is to generate poultry that cannot get flu and would form a ‘buffer between wild birds and humans’”, Barclay said.
Global health and infectious disease specialists cite the threat of a human flu pandemic as one of their major concerns. The death toll in the last flu pandemic in 2009-10 caused by the H1N1 strain and considered to be relatively mild practically took around half a million people worldwide. The historic 1918 Spanish flu killed around 50 million people.
“The greatest fear now is that a deadly strain could jump from wild birds via poultry into humans, and then mutate into a pandemic airborne form that can pass easily between people. If we could prevent influenza virus crossing from wild birds into chickens, we would stop the next pandemic at source”,’ added Barclay.
In the journal “Nature” , a research was published in 2016, whereby Barclay’s team found that a gene present in chickens called ANP32 encodes a protein that all flu viruses depend on to infect a host.
WHAT IS CRISPR-CAS9?
CRISPR-Cas9 is a tool for making precise edits in DNA, discovered in bacteria.
The acronym stands for ‘Clustered Regularly Inter-Spaced Palindromic Repeats’.
The technique identifies a DNA cutting enzyme and a small tag which tells the enzyme where to have a cut. By editing this tag, scientists are able to target the enzyme to specific regions of DNA and make precise cuts, wherever they like. This procedure has been used to ‘silence’ the genes and effectively switching them off. When the cellular mechanism repairs the DNA break, it removes a small clip of DNA. With these findings, the scientists can precisely turn off specific genes in the genome.
At the Roslin, Barclay said, “The plan is to use CRISPR to edit the chicks’ DNA so that only one part of the key protein is changed, leaving the rest of the bird exactly the same, genetically, as it was before. The approach has been used previously to edit the HBB gene responsible for a condition called β-thalassaemia. People eat food from farmed animals that have been altered by decades of traditional breeding”, she said.
“But they might be nervous about eating gene edited food. We have identified the smallest change that will stop the virus in its tracks. One of the biggest hindrances to this approach would be poultry producers’ concerns about public acceptance”, she added.