With Easter just days away, thoughts naturally turn to eggs of the chocolate kind. So here's a question: what's the most valuable egg in Britain?

Forget about the elaborate creations of master chocolatiers. The genetically modified brown eggs produced by a flock of designer hens at the Roslin Institute near Edinburgh are the biotechnological equivalent of a Fabergé.

Several generations of Isa Brown hens - a prolific egg-laying French cross between Rhode Island Red and Rhode Island White - have been bred from "founder birds" that were genetically altered by Dr Helen Sang and her team to contain human genes.

Each gene provides the recipe for the production of a corresponding human protein. In the Roslin Institute hens the human protein is found only in their eggs, reducing the risk of harm to the hens themselves.

The egg proteins are rich in expensive drugs that can fight cancer and other diseases, with each egg containing enough medicine to treat a handful of patients each year.

With this technique, Dr Sang's team has created a potential anti-cancer antibody as well as the drug interferon, marking an important advance in "pharming" - the use of farm animals for the production of pharmaceuticals.

Existing methods for making protein drugs, such as the monoclonal antibodies used to treat cancer and arthritis, are expensive and time-consuming.

Producing protein drugs in the eggs or milk of farm animals is potentially cheaper, faster and more efficient, but researchers have, until now, had only limited success in making pharming workable.

Because GM hens can each lay 300 eggs annually and can make faithful copies of human proteins, they could, within a few years, offer the prospect of mass-producing drugs that currently cost £10,000 a year per patient, at a fraction of today's cost.

Very cool.  More at the link.

Telegraph.uk