Researchers find blue eggs owe their peculiar color to a genetic mutation

Aug 21, 2013 20:36 GMT  ·  By

Certain breeds of chicken lay blue eggs. These eggs are presently marketed by several supermarkets across the world, and the people who have had the chance to give them a try claim that they are tastier than traditional brown and white ones.

Word has it that blue eggs also break better than other varieties, all thanks to the makeup of their shells, and that they are way prettier.

Researchers at the University of Nottingham have spent the past four years researching blue eggs. They now claim that they have determined how and why the world's first blue eggs came into being.

As explained on the University's official website, blue eggs owe their peculiar color to a genetic mutation that first affected a native South American breed of chicken dubbed the Mapuche fowl.

This gene was later passed on to a European descendant of this breed, i.e. the Araucana. This happened sometime between 200 and 500 years ago.

The scientists working on tracking down the blue eggs' origins first examined the genome of the blue egg laying chicken, and determined the exact location of the mutation responsible for the color of their eggs.

They then investigated how this mutation occurred, and determined that a retrovirus that had infected domestic chicken hundreds of years ago was the one to blame.

By the looks of it, this retrovirus managed to incorporate some of its own genetic material into the DNA of the cells it had infected.

This affected the process that leads to the formation of an egg, translated into a green-blue bile pigment known as biliverdin in the eggshell.

Commenting on the importance of this investigation, researcher David Wragg said that, “It [the findings] shows the importance of viruses in shaping evolution and diversity of species.”

The specialist suspects that, but for people's taking the decision to purposely breed chickens with this genetic mutation, blue eggs would've probably disappeared quite a long time ago.

“When appearing in the population, the unusual egg coloration must have attracted the attention of the owners, who must be praised for having selected the trait in subsequent breeding,” he pointed out.