GMO Cow Produces Hypoallergenic Milk

HAMILTON, New ZealandResearchers in New Zealand have successfully bred the first cow in the world to produce high-protein milk that may be hypoallergenic, according to a new study published in the journal Proceedings of the National Academy of Sciences (PNAS). The breakthrough has enormous implications due to its potential to reduce the significant impact milk allergies have on children.

Scientists at AgResearchs Ruakura campus were successful in greatly reducing the amount of beta-lactoglobulin (BLG), a milk whey protein that is not present in human breast milk and which can cause allergic reactions. The discovery is significant because 2% to 3% of infants are allergic to cows milk, and BLG allergies make up a large part of that percentage, the researchers said.

The scientists first tested the process in a mouse model engineered to produce the sheep form of BLG protein in mouse milk. Employing a technique called RNA interference, two microRNAs (short ribonucleic acid molecules) were introduced into the mouse to knock-down the expression of the sheep BLG protein. This resulted in a 96% reduction in the sheep BLG protein in mouse milk.

Next, the scientists produced Daisy, a female calf genetically engineered to express the same two micro RNAs, this time to target the BLG protein that is also a normal constituent in cows milk. They then hormonally induced Daisy to lactate. The resulting milk collected from Daisy had no detectable BLG protein and, unexpectedly, also had more than twice the level of the casein proteins that also normally occur in cows milk.

People have long looked into reducing this enigmatic protein, or completely knocking it out, because there has been no definitive function able to be assigned to it. So, we developed this scientific model to investigate the effect of knocking BLG protein out on the composition and functional properties of milk, and to determine whether the absence of BLG produces cows milk that is hypo-allergenic," said co-author Dr. Stefan Wagner. This is the real discovery component to this project, and Daisy provides us with the opportunity to answer a lot of those questions."

To avoid the delay of two years before a natural lactation, the milk the scientists analyzed was from an induced lactation. They only obtained small quantities over a few days for these initial studies. They now want to breed from Daisy and determine the milk composition and yield from a natural lactation. They also want to investigate the origin of Daisys taillessness, a rare congenital disease in cows.

In the future, the basic process of using designer microRNAs to target other genes could provide an efficient tool to change additional livestock traits, for example to produce animals with enhanced disease resistance and/or improved lactation performance, the scientists said.

For more information about GMOs check out A History of Genetically Modified Crops" image gallery on Food Product Design.