REPORTS that the first cow genetically engineered to be immune to BSE will soon be born have turned out to be misleading.
In theory, creating BSE-free animals is simple: delete both copies of the gene for the PrP protein that causes prion diseases when it becomes mishapen, and animals cannot develop the disease. But in practice, engineering such animals is time-consuming and very costly, and past attempts to create cows that lack the gene have failed (Â鶹´«Ã½, 5 January 2002, p 5).
So when Kirin Brewery of Japan this week announced that a cow was pregnant with a…
