Unscrambling the genetics of the chicken's 'blue' egg

Published on: Aug 20, 2013

They are the latest foodie fashion and look set to become big business in the baking aisles of major supermarkets — the blue egg produced by some chickens is prettier and some say tastier and cleaner-breaking than the brown or white ones — and now, thanks to scientists from The University of Nottingham in the U.K., the genetics is now known that causes the eggs in some breeds to turn this unusual color.

In a four-year research project just published in the journal PLOS ONE, the team from the University of Nottingham School of Biology has identified the genetic mutation that first produced the blue egg in native South American chicken, the Mapuche fowl, and their European descendants, Araucana, between 200 and 500 years ago. The results could inform future research into agricultural breeding techniques if demand for the blue egg continues to grow.

The scientists used the unique genetic resources conserved by heritage or 'fancy' poultry breeders to identify at fine resolution the exact location of the mutation in the genome in blue egg-laying chicken. This work was followed by further genomic study that revealed the genetic cause of the blue colored egg shell — surprisingly — an ancient harmless retrovirus in the domestic chicken.