Using a technique called RNA interference, researchers in New Zealand have genetically engineered a cow to produce anti-allergy milk. The genetically engineered cow produces very little of the protein responsible for causing allergic reaction.
Cows’ milk is known to cause an allergic reaction in some children. Most mothers prefer not to breastfeed infants, while cows’ milk is an increasing source of protein for babies. Some babies have lower tolerance against cows’ milk because of allergic reaction.
In a paper published in the Proceedings of the National Academy of Sciences, the researchers claim that 2 to 3 percent of infants in the developed nations are allergic to cows’ milk in the first year of life.
The component in milk that causes allergic reactions is the protein beta-lactoglobulin (BLG). Anower Jabed and colleagues at the New Zealand government-run AgResearch company claim that their genetically modified cow produces 96 percent less BLG.
There are dairy industry processes to reduce allergenic potential of milk but they are expensive. The milk so produced is also bitter. There is also the possibility of knocking out the gene that produces BLG through genetic engineering. However, the current technique merely suppresses the responsible gene.
According to Bruce Whitelaw, professor of animal biotechnology at the University of Edinburgh, this research is a good example that offers “alternative strategies to current manufacturing process”.
RNA interference has been successfully tried in livestock for the first time. Earlier, the technique was used to manipulate plants and worms.
According to Nature.com:
RNA interference (RNAi) and TALENs (Transcription Activator-Like Effector Nucleases) are more accurate at targeting the gene in question than are earlier genetic engineering techniques. For years, researchers tried to remove the allergy-inducing milk protein beta-lactoglobulin from cow's milk, which can cause diarrhea and vomiting in some toddlers. They tried replacing the gene encoding beta-lactoglobulin with a defective form, but this proved nearly impossible because the techniques available to introduce foreign genes into animal genomes were not precise, and misplaced genes failed to express themselves correctly.
The RNAi technology also offers immense potential as a human therapeutic tool. It has emerged as a powerful technology to down regulate gene expression with the consequence that it can be used in a variety of tissues to knock down target genes responsible for diseases.