Scientists in China say they have successfully engineered genetically modified (GM) cows that show an increased resistance to TB.
Researchers from China’s Northwest A&F University in Shaanxi used a gene-editing technique called clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9n to insert a natural TB resistance-associated macrophage protein NRAMP1 gene into the genetic code of calves.
The transgenic animals subsequently proved more resistant to TB than unmodified animals. The authors also state there were no unintended consequences of the genetic modification.
A study describing the findings has been published in the journal Genome Biology.
When researchers exposed the calves to Mycobacterium bovis, they found the animals showed an increased resistance. They also discovered white blood cells taken from the calves were much more resistant to M bovis in the laboratory.
The authors stated: “To our knowledge, the current study demonstrates the application of a single Cas9n in livestock for the first time.
“This technique aims to efficiently induce gene insertion at a selected bovine locus and produce transgenic cattle with reduced off-target effects. Moreover, we further demonstrated the inserted NRAMP1 was correctly expressed and provided cattle with increased resistance to infection with M bovis, which is the mycobacterial pathogen that causes bTB.”
The authors concluded: “In summary, we demonstrated a single Cas9n can be used for gene insertion at a selected target site in the cattle genome and that this method is advantageous in terms of avoiding additional indel mutations. The resulting transgenic cattle exhibited increased resistance to M bovis infection.
“Our study provides an avenue to develop the CRISPR/Cas9 system for agriculture applications.”
- Read the full story – including reaction from BCVA president Andrew Cobner – in the 27 February issue of Veterinary Times.