Scientists have turned to chickens to help them understand why some people are struck down by severe allergies.
The birds have a "fossilised" version of the key molecule responsible for severe allergic reactions in humans.
King's College London researchers say their findings, published in the Journal of Biological Chemistry, could guide the hunt for future treatments.
Experts said the work offered "exciting new avenues" for research into preventing allergies developing.
The molecule in birds, called IgY, appears to be an ancient forerunner of a similar human molecule called IgE - one of the culprits when the immune system goes into overdrive during asthma attacks or anaphylactic shock.
The King's team are trying to find out why IgE causes a problem, while IgY does not.
