Scientists in New Zealand have created a cow, called Daisy, through the same cloning procedure that was used for creating Dolly the sheep in 1996.The researchers genetically engineered the cow so that it would produce milk free of beta-lactoglobulin (BLG) protein which can cause an allergic reaction in infants. This protein is not present in human milk so babies only show signs of a reaction when they move on to bottled cow’s milk. Approximately one in twelve babies develop an allergic reaction to whey. Most however overcome this but a few remain lactose intolerant for the remainder of their lives.
To make Daisy scientists took a cow skin cell and genetically modified it to produce molecules that block the manufacture of the BLG protein. The nucleus of this cell was then transferred into a cow egg that had its own nucleus removed. The reconstituted egg was cultivated in the laboratory until it formed a blastocyst which was then transplanted into the womb of the foster cow.
Reports suggest that the cloning technique was highly inefficient. Out of around 100 implanted blastocysts only one calf, Daisy, has been born.
One troubling side effect of this experiment is that Daisy was born without a tail. It seems likely that the cloning procedure was responsible for this defect. If the cow is missing a tail, is there any other organ missing from the animal. Although the milk Daisy produces is free of BLG, the overall effect of this on her milk yield is unknown. Another uncertainty is whether any calves produced by Daisy will naturally produce milk free of BLG.
Under European law food products, including milk from cloned animals, must be assessed for safety and approved for sale before they can be marketed.
From an ethical standpoint how do people feel about genetically modifying animals to combat diseases or to make available products that are free from nasties? In 2011 it was rumoured that the Roslyn Institute was working on a technique to create chickens that cannot spread avian flu. What are the advantages and what are the dangers of such experiments?
Hokmah 