By Hannah Bergin
Genetic modification is where the genes of an organism, such as a plant or animal are altered. It has applications largely in agriculture with the ultimate goal to increase nutritional value of food and to optimize production. In some cases genetic modification is used to eliminate proteins found in foods that cause allergies in humans. Research is currently being conducted into the genetic modification of dairy cows such that they produce hypoallergenic milk.
Betalactoglobulin (BGL) is a protein found in cow’s milk that causes cow milk protein allergy (CMPA), which affects between 1.9-4.9% of infants and young children. Of those with the CMPA, approximately 50-60% will suffer from gastrointestinal and skin symptoms and 30% will suffer form respiratory symptom. Children with CMPA are more vulnerable to growth retardation, reduced IQ, altered work habits and altered work habits. There are also links to sleep disruption and a reduction in nutrient absorption due to poor nutritional status. It has been found that many children with CMPA also have additional food allergies, which adversely affects their nutrition. The greatest problem that arises from CMPA is possible malnutrition, as children with CMPA must follow a diet free from cows milk and any cow milk derivatives
(Meyer, Venter, Fox, & Shah, 2012). The
prevalence of CMPA has prompted research in the genetic modification of dairy
cows to eliminate the protein responsible for CMPA. In New Zealand a team of
researchers has genetically modified a cow to produce hypoallergenic milk (Hamzelou, 2012). Researchers
identified the genetic code for BGL and used this to fabricate a complimentary
genetic code that when injected into the nucleus of a cell, shuts downs the
production of this protein. The treated nucleus was transferred into a cow egg
cell, which was fertilized and implanted into another cow (Hamzelou,
This cow gave birth to a healthy female cow. Notably, the calf, whilst healthy,
was born without a tail. The calf was treated with hormones to provoke early
lactation so that the milk could be analyzed. It was found that the BGL protein
was absent in the milk. This is what gives the genetically modified cows milk
its “hypoallergenic” property. The researchers have not yet been able to
investigate the effects of the composition of this milk in terms of taste or
nutritional value at this stage due to stringent regulations. What they have
found though is that the milk, whilst completely lacking BGL protein, had
significantly higher levels of other proteins than normal. How this affects the
milk in terms of its nutritional value will need investigation before it can be
marketed. Also, the effect of a cow not having a tail will need to be
considered in terms of breeding the genetically modified livestock.
Hamzelou, J. (2012). Calf Produces Worlds First Hypoallergenic Milk. NewScientist .
Meyer, R., Venter, C., Fox, A. T., & Shah, N. (2012). Practical Dietary management of protein energy malutrition in young children with cow's milk protein allergy. Paediatric allergy and immunology , 307-314.